Chemistry terminology · MLC-0109

Chemistry terms: P (1,381)

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• Packed columnA chromatographic column that contains a solid stationary phase or a liquid stationary phase coated on a...
• PackingThe solid material that fills a chromatographic column, serving as the stationary phase or as a support for...
• Packing of chain stemsThe arrangement of the relatively straight, extended segments of polymer chains within the crystalline...
• PaddlanesTricyclic saturated hydrocarbons in which two bridgehead carbon atoms are joined by four bridges, giving a...
• Π-adductA species formed by the association of an electrophile or nucleophile with the pi (π) electron system of an...
• PainAn unpleasant sensory and emotional experience that is typically associated with actual or potential tissue...
• Pair attenuation coefficientA measure of the probability that a photon will undergo pair production per unit thickness of a material...
• Pair correlation lengthA measure of the average distance over which the positions or orientations of particles in a system are...
• Pair productionA nuclear process in which a high-energy photon, typically a gamma ray, interacts with the electric field of...
• Paired helical filamentAn abnormal fibrillar structure found in the brains of individuals with Alzheimer's disease and other...
• Pake doubletA characteristic two-line splitting pattern observed in solid-state nuclear magnetic resonance (NMR) spectra...
• PalaeontologyThe scientific study of life from past geological ages, based on the analysis of fossils of plants, animals...
• PalateThe roof of the mouth in vertebrates, forming a partition between the oral and nasal cavities. It consists of...
• Palatine rapheA raised ridge of tissue running along the midline of the hard palate, extending from the incisive papilla...
• Pallmann effectThe observed difference in pH between a colloidal suspension and its equilibrium dialysate, typically...
• PalpitationA subjective sensation of an abnormal heartbeat, perceived by the individual as unusually rapid, forceful...
• PAN-based carbon fibresCarbon fibers produced from polyacrylonitrile (PAN) precursors through a series of thermal treatments...
• PancytopeniaA shortage of all three kinds of blood cell at once: red cells (anemia), white cells (leukopenia) and...
• Papanicolaou smearA cytological screening method for detecting precancerous and cancerous conditions of the uterine cervix. The...
• PapilledemaA swelling of the optic disc, the point where the optic nerve enters the retina, caused by elevated...
• Paracortical areaThe region within a lymph node located between the outer cortex, which contains B-cell follicles, and the...
• ParacrineA type of cell signaling where a cell produces a signaling molecule that acts on nearby target cells. The...
• ParacrystalA material structure exhibiting a degree of order intermediate between that of a perfect crystal and an...
• Paracrystalline disorder of the first kindStructural disorder of a paracrystal in which atoms are displaced from their average lattice positions by...
• Paracrystalline disorder of the second kindStructural disorder of a paracrystal in which atoms are permanently displaced from the ideal lattice...
• Paracrystalline distortion factorA quantitative measure that describes the extent of structural disorder within a paracrystalline material. It...
• ParadigmA framework of concepts, theories, methods, and standards that constitutes an accepted approach to a...
• ParaffinA common name for alkanes, which are saturated hydrocarbons containing only single carbon-carbon and...
• Paraffin impregnated graphite electrodeA type of carbon electrode where the pores of a graphite rod are filled with paraffin wax. This impregnation...
• Parafollicular cellA neuroendocrine cell type found in the thyroid gland, distinct from the follicular cells that produce...
• Parallel artificial liquid membrane extractionA high-throughput extraction technique that uses an array of artificial liquid membranes to simultaneously...
• Parallel effectThe shift in position of a transition state along the minimum-energy reaction path when a structure lying on...
• Parallel factors analysisA multi-way decomposition method used in chemometrics to analyze data arrays with three or more modes, such...
• Parallel synthesisA synthetic methodology where multiple chemical reactions are performed simultaneously to create a library of...
• Parallel-chain crystalA crystalline structure in polymers where the individual polymer chains are aligned predominantly parallel to...
• ParalysisThe complete loss of muscle function in a part of the body, resulting from damage to the nervous system. This...
• Paralytic shellfish poisoningA severe form of food poisoning caused by consuming shellfish contaminated with saxitoxins, potent...
• ParamagneticDescribing a substance that is weakly attracted to an external magnetic field due to the presence of unpaired...
• Paramesonephric ductOne of a pair of embryonic ducts of mesodermal origin, also called Müllerian ducts, that give rise in the...
• Parametric amplificationA process in which a signal is amplified by varying a parameter of the system at twice the signal frequency...
• Parametric processesNonlinear optical phenomena where the properties of a medium are modulated by an intense pump beam, leading...
• ParametriumThe connective tissue surrounding the uterus, extending laterally between the layers of the broad ligament...
• ParamoneA paracrine agonist, meaning a signalling molecule that is released by one cell, diffuses through the...
• Paraneoplastic autoimmune syndromeA group of disorders characterized by neurological or systemic dysfunction that arises in individuals with...
• Para-occupational exposureExposure to hazardous substances that occurs in individuals who are not directly involved in the occupational...
• ParaoxonaseAn enzyme, specifically an aryldialkylphosphatase, that hydrolyzes organophosphates, including the toxic...
• ParaplegiaParalysis that affects the lower half of the body, including both legs, and sometimes parts of the trunk...
• Parasitic twinA severely malformed fetus that is physically attached to a more developed, relatively normal co-twin, known...
• ParasympatheticRelating to the parasympathetic nervous system, a division of the autonomic nervous system responsible for...
• Parasympathetic nervous systemA division of the autonomic nervous system that conserves energy and promotes 'rest and digest' functions. It...
• ParasympatholyticA substance or drug that inhibits the activity of the parasympathetic nervous system. These agents block the...
• ParasympathomimeticA substance that mimics the effects of stimulating the parasympathetic nervous system. These agents act...
• ParatopeThe specific region on an antibody molecule that recognizes and binds to an antigen. This site is formed by...
• Paraxial mesodermThe region of the mesoderm in a developing embryo that is situated alongside the neural tube. During...
• Parenchymal cellA cell of the functional tissue of an organ or gland, as opposed to the connective tissue framework of...
• Parent hydrideA fundamental acyclic or cyclic hydride from which the names of many organic compounds are systematically...
• Parent ionAn electrically charged species that dissociates to give fragments, at least one of which is charged and at...
• Parenteral dosageThe administration of a substance into the body by routes other than the digestive tract, such as...
• ParesisA condition characterized by partial or incomplete loss of motor function or muscle weakness, rather than...
• ParesthesiaAn abnormal sensation of the skin, such as tingling, prickling, chilling, burning, or numbness, with no...
• Pareto frontA set of solutions in multi-objective decision-making where no single objective can be improved without...
• Pareto optimizationA method of finding solutions to multi-objective optimization problems where no single objective can be...
• ParietalRelating to the walls of a body cavity or to the outer layer of an organ. In anatomy, it distinguishes...
• Parietal lobeA major division of the brain located behind the frontal lobe and above the temporal lobe. It is primarily...
• Pariser-Parr-Pople methodA semi-empirical molecular orbital method used in quantum chemistry to calculate the electronic structure of...
• Parkinson diseaseA progressive neurodegenerative disorder characterized by motor symptoms such as tremor, rigidity...
• ParthenogenesisA form of asexual reproduction in which an embryo develops from an unfertilized egg cell. This process occurs...
• Partial agonistA ligand that binds to and activates a receptor but produces only a partial response compared to a full...
• Partial anodic currentThe component of the total current flowing across an electrode-electrolyte interface that is associated with...
• Partial atomic chargesCalculated values assigned to individual atoms within a molecule to represent the unequal distribution of...
• Partial charge exchange reactionA gas-phase ion-neutral reaction in which a multiply charged ion captures one electron from a neutral...
• Partial charge transfer reactionA reaction between an ion and a neutral species in which a multiply charged reactant ion has its charge...
• Partial decay constantThe probability per unit time that a given radionuclide will undergo a specific mode of radioactive decay...
• Partial digestionA chemical or physical process that incompletely breaks down a sample material, leaving some components...
• Partial free-drainingA hydrodynamic condition for a polymer coil in solution where the solvent molecules can partially penetrate...
• Partial ion yieldThe number of ions of a specific type produced per incident particle or unit of sputtered material during a...
• Partial isothermA graphical representation showing the amount of a single component adsorbed onto a surface from a liquid...
• Partial isotopic scramblingThe incomplete redistribution of isotopes within a molecule or ion during a chemical reaction or...
• Partial killThe reduction in the population of organisms or cells, but not their complete eradication, following exposure...
• Partial kinetic currentThe component of the total current at an electrode that is limited by the rate of a chemical reaction...
• Partial least squaresA statistical method that relates a set of predictor variables to a set of response variables by projecting...
• Partial least squares discriminant analysisA chemometric classification method that combines features of partial least squares regression and...
• Partial least squares regressionA multivariate statistical method that relates a set of predictor variables to a set of response variables by...
• Partial mass densityA partial quantity, equal to the change in mass of a system when a small amount of a component is added...
• Partial molar quantityThe change in an extensive thermodynamic property of a solution per mole of a specific component added, while...
• Partial rate factorA quantitative measure of the reactivity of a specific position in an aromatic compound towards electrophilic...
• Partial specific volumeThe rate at which the volume of a system grows with the mass of one added component, that is the volume...
• Partial sputtering yieldThe number of atoms or molecules of a specific species ejected from a solid surface per incident particle...
• Partially drainingA description of the hydrodynamic interaction between a polymer coil and the surrounding solvent, where the...
• Partially engulfed particleA multicomponent polymer particle in which one polymer wraps most of the other polymer's surface without...
• Participant in an interlaboratory comparisonA laboratory that receives samples or test items from a coordinator and performs measurements or tests on...
• Particle beam interfaceA device used in mass spectrometry to introduce analytes from a liquid chromatograph into the high vacuum of...
• Particle concentrationThe amount of airborne particulate matter per unit volume of air, expressed either as mass concentration...
• Particle densityThe number of particles, such as nuclei or elementary particles, divided by the volume that contains them, a...
• Particle flux densityThe number of particles or photons incident per unit time on a unit area of a plane perpendicular to the beam...
• Particle immunoassayA type of immunoassay that uses particles, such as latex beads or magnetic beads, as solid supports for the...
• Particle induced X-ray emission analysisAn analytical technique that uses a beam of energetic charged particles, such as protons, to excite atoms in...
• Particle monolayerA single layer of particles adsorbed or deposited at an interface, such as a liquid-air or liquid-liquid...
• Particle number concentrationThe number of individual particles present per unit volume of a dispersed system. This quantity is a...
• Particle scattering functionA mathematical function that describes the angular dependence of scattered radiation intensity from a single...
• Particle sizeA measure of the physical dimensions of solid or liquid particles suspended in a gas, such as those...
• Particle size distributionA statistical representation of the range of particle sizes present in a given sample and their relative...
• Particle sorbentA solid material in the form of discrete particles used in extraction techniques to selectively adsorb or...
• Particle-diameter dispersityA measure of the breadth of the distribution of particle diameters within a dispersed system. It quantifies...
• Particle-embedded glass fibre discA filtration medium consisting of glass fibers with finely divided sorbent particles uniformly dispersed and...
• Particle-induced gamma-ray-emission analysisA nuclear analytical technique that identifies and quantifies elements in a sample by detecting...
• Particle-loaded membrane discA thin, porous membrane impregnated with sorbent particles, designed for rapid extraction and...
• Particular propertyA specific characteristic or attribute of a component in a system, defined for a given kind of quantity. This...
• Particulate carbonFinely divided solid carbon material existing as discrete particles, rather than as a continuous bulk solid...
• Particulate gelA type of gel formed by the aggregation and interconnection of discrete colloidal particles, rather than by...
• Particulate matterFinely divided solid or liquid particles suspended in a gas, such as the atmosphere. These particles vary...
• Particulate solA colloidal dispersion whose dispersed phase is made of separate particles that are not macromolecules, as...
• PartitionThe distribution of a solute between two immiscible or partially miscible phases at equilibrium. This process...
• Partition chromatographyA chromatographic technique where separation of analytes occurs primarily based on their differential...
• Partition coefficientThe ratio of the concentration of a solute in one phase to its concentration in a second, immiscible phase at...
• Partition constantThe equilibrium constant for the distribution of a solute between two immiscible phases, expressed as the...
• Partition functionA fundamental quantity in statistical mechanics that describes the statistical properties of a system in...
• Partition isothermA graphical representation showing the relationship between the concentration of a solute in the stationary...
• Partition ratioThe ratio of the total amount of a solute in the stationary phase to the total amount of the solute in the...
• ParturitionThe physiological process of giving birth, involving a complex series of hormonal and mechanical events that...
• PascalThe SI derived unit of pressure, stress, and Young's modulus, symbolized as Pa. One pascal is defined as the...
• Pass energyThe kinetic energy at which ions or electrons are allowed to traverse the analyzer section of an electron or...
• PassivationThe process by which a metal or other material becomes less susceptible to corrosion or reaction due to the...
• Passivation potentialThe most negative electrode potential at which a metal or alloy transitions from an active corrosion state to...
• Passive avoidance testA behavioral assay used to assess learning and memory in rodents, particularly fear-motivated learning. An...
• Passive cutaneous anaphylaxis testAn in vivo assay used to detect the presence of allergen-specific IgE antibodies in serum. Serum from a...
• Passive hemagglutinationAn immunological technique where red blood cells are coated with soluble antigens and then used to detect...
• Passive immunizationThe transfer of pre-formed antibodies from one individual to another to provide immediate, but temporary...
• Passive metalA metal that exhibits significantly reduced reactivity or corrosion rate due to the formation of a thin...
• Passive samplerA device used for environmental monitoring that collects airborne or waterborne contaminants by diffusion or...
• Passive samplingA sampling technique where analytes are collected from a medium by diffusion or permeation into a sampling...
• Passive smokingThe breathing in of tobacco smoke by non-smokers who share air with smokers, known as exposure to...
• Passive stateThe condition of a metal surface where its corrosion rate is significantly reduced due to the formation of a...
• PasteA semi-solid dosage form intended for external application to the skin or mucous membranes, characterized by...
• Patch testA diagnostic procedure used to identify substances that cause allergic contact dermatitis. Small amounts of...
• Patent ductus arteriosusA congenital heart defect in which the ductus arteriosus, a blood vessel connecting the aorta and pulmonary...
• PatentabilityThe set of legal conditions an invention must meet to be granted a patent, generally novelty, an inventive...
• Path fingerprintsA type of molecular fingerprint that encodes the presence or absence of specific linear paths of atoms and...
• Path lengthThe number of backbone atoms of a polymer that lie between two specified subunits. If a ring or ring system...
• Pathogen-associated molecular patternMolecular structures found on or within microorganisms that are recognized by the innate immune system of a...
• PathwayA series of linked chemical reactions, usually catalysed by enzymes, that converts a starting biological...
• pATR spectrumAn infrared absorption spectrum obtained using attenuated total reflection (ATR) spectroscopy, where the...
• Pattern collapseThe mechanical failure of high-aspect-ratio polymer structures during or after the development process in...
• Pattern recognitionThe process of identifying and classifying data based on recurring features or patterns. In computational...
• Pattern recognition receptorA type of receptor expressed by cells of the innate immune system that recognizes conserved molecular...
• Pattern transferThe process in lithography of replicating a pattern from a resist layer into an underlying substrate...
• Patterns of reactivity schemeA method for predicting the monomer reactivity ratios r12 and r21 of a binary copolymerization from...
• Paucidisperse systemA colloidal system characterized by a small, discrete number of distinct particle sizes or size ranges...
• Pauci-immuneDescribing a form of tissue injury, particularly in glomerulonephritis and vasculitis, characterized by the...
• Paul ion trapAn ion trap that holds charged particles in a three-dimensional quadrupole field generated by a...
• Pauli exclusion principleA quantum mechanical principle asserting that no two identical fermions, such as electrons, can occupy the...
• Paw-reaching testA behavioral assessment used in neuroscience to evaluate fine motor coordination and skilled forelimb...
• PC-12 cellA cell line derived from a rat pheochromocytoma, a tumor of the adrenal medulla. These cells exhibit...
• Π-conjugated systemA molecular system containing a series of alternating single and multiple bonds, or a system with delocalized...
• PeakA localized maximum in a chromatogram or spectrum, representing the response of a detector to a specific...
• Peak analysisThe process of identifying, quantifying, and characterizing individual peaks within a spectroscopic or...
• Peak areaThe integrated signal intensity of a chromatographic peak or spectral band, representing the total amount of...
• Peak area methodA quantitative analytical technique that determines the concentration of an analyte by measuring the area...
• Peak baseThe segment of the chromatogram baseline that lies between the beginning and the end of a chromatographic...
• Peak concentrationThe maximum concentration of a substance recorded in a specific medium, such as air or water, during a...
• Peak currentThe maximum current observed in a voltammetric experiment, occurring at a specific potential as the analyte...
• Peak elution volumeThe volume of mobile phase that passes through a chromatographic column from the point of sample injection...
• Peak energyThe energy value corresponding to the maximum intensity of a spectral peak, often observed in techniques like...
• Peak fittingA mathematical procedure used to decompose a complex spectral band into its individual component peaks. This...
• Peak heightThe maximum vertical distance from the peak maximum to the baseline of a chromatographic or spectral peak...
• Peak matchingA technique in mass spectrometry where the exact mass of an unknown ion is determined by comparing its...
• Peak maximumThe point on a chromatographic or spectral peak where the signal intensity reaches its highest value. This...
• Peak parkingA tactic in liquid chromatography coupled to mass spectrometry for gaining extra time to analyse a component...
• Peak potentialThe potential at which the maximum current is observed in a voltammetric experiment, corresponding to the...
• Peak resolutionA quantitative measure of the separation between two adjacent peaks in a chromatogram or spectrum. It is...
• Peak strippingA data treatment step in elemental mass spectrometry for an unresolved multiplet peak, where part of the...
• Peak width at baseThe horizontal distance along the baseline between the two points where a chromatographic peak begins and...
• Peak width at half heightThe horizontal distance across a chromatographic or spectral peak measured at half of its maximum height...
• Peak widthsA measure of the breadth of a chromatographic peak, indicating the dispersion of a solute as it passes...
• Pearl-necklace modelA theoretical model used to describe the hydrodynamic behavior of a flexible polymer chain in solution...
• PectinsA group of complex polysaccharides found in the cell walls of plants, primarily composed of D-galacturonic...
• Peierls distortionA distortion of the crystal lattice in one-dimensional metallic or semiconducting systems that leads to a...
• Peierls transitionA structural distortion in a quasi one-dimensional metal, usually a pairing of atoms along the chain, that...
• PelagicDescribing the open water column of a sea, lake, or ocean, distinct from the bottom (benthic) or coastal...
• Π-electron acceptor/donor groupA substituent group that either withdraws or donates electron density through a pi (π) bond system. A...
• Π-electron donorA chemical species that possesses a high-energy pi (π) electron system, making it capable of donating these...
• PelletA small, spherical or semi-spherical solid dosage form composed of agglomerated fine powders or granules of...
• PelletisationThe process of converting fine powders or granules into small, free-flowing, and spherical or semi-spherical...
• Pellicular packingA type of stationary phase material used in chromatography, consisting of solid, non-porous beads coated with...
• Pelvic kidneyA congenital anomaly where one or both kidneys are located in the pelvis rather than in their normal position...
• PemphigusA group of rare autoimmune diseases characterized by the formation of blisters and erosions on the skin and...
• PenamsA class of bicyclic organic compounds characterized by a fused beta-lactam ring and a five-membered...
• Pendant groupA substituent group that is attached to the main chain of a polymer but is not part of the main chain itself...
• Pendent chainA polymer chain or segment that is attached to a larger macromolecule or network at only one point...
• PenemsA class of bicyclic organic compounds featuring a fused beta-lactam ring and a five-membered unsaturated...
• PenetrantA substance in the fluid phase that diffuses into a solid or liquid, such as a polymer membrane. The movement...
• PenetrationThe process by which a substance passes through a barrier, such as a biological membrane or a protective...
• PenicillinsA group of β-lactam antibiotics derived from the fungus Penicillium, characterized by a penam core structure...
• Penning excitationAn energy transfer process where an excited metastable atom or molecule transfers its excitation energy to...
• Penning gas mixtureA mixture of gases, typically a noble gas with a small amount of an easily ionizable gas, designed to enhance...
• Penning ion trapA type of ion trap that uses a strong static magnetic field and a weaker static electric field to confine...
• Penning ionizationA process where an excited neutral atom or molecule, typically in a metastable state, collides with another...
• Pentaprismo-A prefix in names for a structure whose ten atoms sit at the vertices of a pentagonal prism, a solid with two...
• Penultimate-unit effectThe influence of the monomer unit located second-to-last from the growing end of a polymer chain on the...
• Peptide de novo sequencingThe process of determining the amino acid sequence of a peptide directly from its tandem mass spectrometry...
• Peptide fragment ionAn ion produced when a peptide precursor ion undergoes dissociation, typically through collision-induced...
• Peptide fragmentation techniqueA method used in mass spectrometry to induce the dissociation of peptide ions into smaller fragment ions...
• Peptide mass fingerprintingA protein identification technique where a protein is first digested into smaller peptides using a specific...
• Peptide nucleic acidA synthetic polymer that mimics the structure of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) but...
• Peptide precursor ionAn ionized peptide molecule that is selected for fragmentation in a tandem mass spectrometry experiment. This...
• Peptide sequence tagA short, experimentally determined amino acid sequence derived from the fragmentation spectrum of a peptide...
• Peptide tetramerA reagent made of four biotinylated peptide-MHC complexes held together by one fluorescently labelled...
• Peptide vaccineA type of subunit vaccine that uses short, synthetic chains of amino acids corresponding to the epitopes of a...
• Peptide-binding grooveA specific cleft or pocket located on the surface of major histocompatibility complex (MHC) molecules...
• PeptidesCompounds consisting of two or more amino acid residues linked in a chain, where the carboxyl group of each...
• PeptidoglycanA polymer forming a major structural component of the cell walls of most bacteria. The molecule is a...
• PeptidomicsThe systematic study of the entire set of peptides present in a biological sample, known as the peptidome...
• PeptizationThe process of converting a coagulated or flocculated precipitate back into a stable colloidal dispersion...
• PeptoidA class of synthetic polymers that are structural mimics of peptides, also known as poly-N-substituted...
• Per capita birth rateThe average number of births per individual in a population over a specific period. This rate is a...
• Per capita death rateThe average number of deaths per individual in a population over a defined period. This rate is a key...
• Per capita rate of increaseThe average change in population size per individual over a specific time period, reflecting the balance...
• PercentA dimensionless unit used to express a fraction of a whole as parts per hundred. It is calculated by dividing...
• Percentage exposedThe fraction of the total number of atoms of a given element in a catalyst that are present on the surface...
• Percentage relative errorA measure of the accuracy of an analytical result, expressed as the absolute relative error multiplied by...
• Percentage standard deviationA measure of the precision of a set of analytical measurements, calculated as the standard deviation divided...
• Percentage transmissionThe ratio of the radiant power transmitted through a sample to the radiant power incident upon it, expressed...
• PercolationThe formation of a continuous path or network through a disordered medium, such as a polymer composite filled...
• Percolation thresholdThe specific concentration or volume fraction of a dispersed phase within a composite material at which a...
• PercutaneousDescribing the passage of a substance into or through the skin. This route of exposure or administration...
• Perfect networkA theoretical polymer network in which all polymer chains are elastically active and contribute to the...
• Perfectly polarized interphaseAn interface between two phases, typically an electrode and an electrolyte, across which no charge transfer...
• PerforinA pore-forming protein released by cytotoxic T lymphocytes and natural killer cells. This protein inserts...
• Performance characteristic of a measurement procedureA functional quality used to describe and evaluate the capabilities of an analytical measurement procedure...
• Performance scoreA quantitative measure used to evaluate the analytical capability of a laboratory or an individual analyst in...
• PerfusateThe fluid pumped into a dialysis or microdialysis probe, which serves as the extraction phase and takes up...
• Perfusion stationary phaseA type of stationary phase used in liquid chromatography characterized by large pores that allow the mobile...
• Periarteriolar lymphoid sheathA cylindrical mass of lymphoid tissue that surrounds the central arteries within the white pulp of the...
• PericardiumA double-layered sac that encloses the heart and the proximal portions of the great blood vessels. The outer...
• Pericyclic reactionA type of organic reaction that proceeds through a single, concerted transition state involving a cyclic...
• Perikinetic aggregationThe process of particle aggregation in a colloidal suspension driven by random Brownian motion, where...
• Perikinetic coagulationThe aggregation of colloidal particles driven by their random thermal motion, known as Brownian motion. This...
• PerinatalRelating to the period of time immediately before and after birth. The exact duration covered by the term...
• PerineumThe surface region in both males and females between the pubic symphysis and the coccyx. Anatomically, it is...
• PeriodThe time taken for one full cycle of a periodic phenomenon such as an oscillation or wave, equal to the...
• Periodic copolymerA copolymer whose macromolecules contain more than two kinds of monomeric units arranged in a regular...
• Periodic copolymerizationA copolymerization process that results in the formation of a periodic copolymer, where the monomeric units...
• Periodic voltageAn electrical potential that varies regularly over time, repeating a specific waveform at a constant...
• PeriodontitisA chronic inflammatory disease affecting the tissues supporting the teeth, including the gums, periodontal...
• Peripheral atomAn atom in a molecular structure that is not directly involved in the primary reaction center or the core...
• Peripheral bloodBlood circulating throughout the body in the cardiovascular system, excluding that found within the bone...
• Peripheral blood leukocyteAny white blood cell circulating in the bloodstream, as opposed to those residing in lymphoid organs or other...
• Peripheral blood mononuclear cellA type of white blood cell characterized by a single, round nucleus, found in the circulating blood. This...
• Peripheral lymphoid organA specialized tissue structure where lymphocytes encounter antigens and undergo activation, proliferation...
• Peripheral nervous systemThe part of the nervous system that lies outside the brain and spinal cord, consisting of all the nerves that...
• Peripheral neuropathyA condition resulting from damage to the peripheral nerves, which are located outside the brain and spinal...
• Peripheral toleranceAn immunological process that induces unresponsiveness in self-reactive T cells and B cells after they have...
• PeriphytonA complex community of microorganisms, including algae, cyanobacteria, heterotrophic microbes, and detritus...
• PeriselectivityThe selectivity observed in pericyclic reactions where a reactant can undergo several different pericyclic...
• PeristalsisThe rhythmic, wave-like contractions of smooth muscle that propel contents through tubular organs...
• Peritectic reactionAn invariant reaction in a phase diagram where a liquid phase and a solid phase react isothermally to form a...
• Peritectoid reactionAn invariant reaction in a phase diagram where two solid phases react isothermally to form a new, different...
• Peritectoid temperatureThe specific temperature at which a peritectoid reaction occurs in a solid-state system. At this invariant...
• Peritoneal cavityThe potential space between the parietal peritoneum, which lines the abdominal wall, and the visceral...
• Peritoneal dialysisA medical procedure for treating kidney failure by filtering waste products from the blood inside the...
• PeritoneumThe thin serous membrane of the abdomen and pelvis, formed of a parietal layer against the body wall and a...
• Peritonic reactionAn isothermal, isobaric reversible reaction in a ternary solubility system in which a saturated liquid and...
• Permanent crosslinkA chemical bond or junction that irreversibly connects two or more polymer chains, forming a stable...
• Permanent modifierA chemical substance added to the graphite furnace in electrothermal atomic absorption spectroscopy to alter...
• PermeabilityA measure of the ability of a material to allow the passage of a fluid or a magnetic field through it. In the...
• Permeability coefficientA quantitative measure of the rate at which a substance can pass through a barrier, such as a biological...
• Permeability of vacuumA fundamental constant, written μ₀, that relates magnetic flux density to magnetizing field strength in a...
• PermeableDescribing a material or membrane that allows the passage of substances through its structure. This property...
• PermeateThe portion of a fluid mixture that passes through a selective membrane. This stream is enriched in the...
• PermeationThe process by which a substance passes through a barrier or membrane. This movement occurs due to a...
• Permeation chromatographyA chromatographic technique that separates molecules based on their size as they pass through a porous...
• Permeation tubeA device used to generate a constant, low concentration of a gas or vapor by permeation through a polymeric...
• PermilA unit of measurement representing one part per thousand, equivalent to 0.1 percent or 10⁻³. It is commonly...
• PermittivityA measure of how an electric field is affected by a dielectric medium, representing the ability of the...
• Permittivity of vacuumA fundamental constant, written ε₀, that relates electric displacement to electric field strength in a vacuum...
• PermselectivityThe property of a membrane or material that allows certain species to pass through more readily than others...
• Pernicious anemiaAn autoimmune condition characterized by a deficiency in vitamin B12, caused by the body's inability to...
• PeroxidesChemical compounds containing a peroxide group, which is a single bond between two oxygen atoms (-O-O-)...
• PeroxisomeA small, membrane-bound organelle found in the cytoplasm of eukaryotic cells, containing enzymes involved in...
• Peroxy acidsCompounds in which the acidic hydroxyl group of an acid, usually a carboxylic acid, is exchanged for a...
• Perrin equationAn equation that gives the rotational diffusion coefficient of an isolated dissolved molecule or dispersed...
• Persistence lengthA measure of the stiffness or rigidity of a polymer chain, representing the characteristic length over which...
• PersistentDescribing a chemical species, such as a radical or an intermediate, that has an unusually long lifetime...
• Persistent inorganic pollutantAn inorganic chemical substance that resists environmental degradation and remains in the environment for...
• Persistent organic pollutantAn organic chemical substance that resists environmental degradation through chemical, biological, and...
• Personal monitoringThe measurement of an individual's exposure to chemical, physical, or biological agents in their immediate...
• Personal protective deviceAny equipment worn by an individual to minimize exposure to hazards that cause serious workplace injuries and...
• Personal samplerA portable device worn by an individual to collect air samples or measure environmental parameters in their...
• Perspective formulaA two-dimensional representation of a three-dimensional molecule that uses wedges and dashed lines to...
• PerstractionA membrane-based separation process that combines permeation through a membrane with extraction into a liquid...
• Perturbation theoryA mathematical method used in quantum mechanics to approximate the solutions to a complex quantum system by...
• Perturbed angular correlation spectrometryA nuclear spectroscopic technique that measures the interaction between the nuclear magnetic dipole or...
• Perturbed dimensionsThe actual dimensions of a polymer chain in a solvent, which are influenced by interactions between polymer...
• PervaporationA membrane-based separation process that involves the selective permeation of a component from a liquid...
• PestAny organism that is detrimental to humans or human concerns, such as agriculture, livestock, or property...
• PesticideAny substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any...
• Pesticide residueThe small amount of pesticide or its breakdown products that remains on or in food, feed, or environmental...
• PetaA prefix in the International System of Units (SI) denoting a factor of 10^15. It is used to form decimal...
• Petroleum cokeA carbonaceous solid residue derived from the thermal cracking of heavy petroleum fractions, such as vacuum...
• Petroleum pitchA viscous, dark, amorphous residue obtained from the distillation or thermal treatment of petroleum. It is...
• PexophagyThe selective degradation of peroxisomes by the cellular process of autophagy. This quality control mechanism...
• Peyer’s patchAn organized aggregate of lymphoid follicles found in the wall of the small intestine, particularly the...
• P-glycoproteinA membrane-bound transport protein that actively pumps a wide variety of substances out of cells, a process...
• pHA numerical scale that quantifies the acidity or alkalinity of an aqueous solution. It is defined as the...
• pH glass electrodeAn electrochemical sensor used to measure the hydrogen ion activity, and thus the pH, of a solution. It...
• pH gradientA spatial variation in hydrogen ion concentration within a medium, such as a gel or solution. In...
• pH0.5 or pH1/2The pH of the aqueous phase at which the distribution ratio of a solute equals one at equilibrium. The solute...
• Phage displayA laboratory technique used to study protein-protein, protein-peptide, and protein-DNA interactions by...
• PhagocyteA type of cell that engulfs and digests foreign particles, microorganisms, and cellular debris through a...
• Phagocytic activity assayA laboratory procedure for quantifying the ability of phagocytic cells, such as macrophages or neutrophils...
• PhagocytosisThe cellular process by which phagocytes engulf solid particles, such as bacteria, dead cells, or debris...
• PhagolysosomeAn intracellular organelle formed by the fusion of a phagosome, which contains ingested material, with a...
• PhagosomeA membrane-bound vesicle formed inside a phagocytic cell during the process of phagocytosis, containing the...
• Phantom chain behaviourA theoretical model for polymer networks where the network junctions are assumed to be able to pass through...
• Phantom painThe sensation of pain or other feelings, such as itching or pressure, that appear to originate from a body...
• PharmaceuticalA substance or preparation used in medicine for the diagnosis, treatment, or prevention of disease. These...
• Pharmaceutical equivalenceThe relationship between drug products that contain the same amount of the same active substance in the same...
• PharmaceuticsThe discipline concerned with the design, development, and manufacturing of dosage forms for therapeutic...
• PharmacodynamicsThe study of the biochemical and physiological effects of drugs on the body and their mechanisms of action...
• PharmacogeneticsThe study of how genetic variations among individuals influence their responses to drugs. It focuses on...
• PharmacogenomicsThe study of how an individual's entire genome influences their response to drugs. This broader field...
• PharmacokineticsThe study of the time course of a substance and its metabolites within a living organism, encompassing the...
• PharmacologicalRelating to the study of how chemical substances interact with living systems, particularly in the context of...
• Pharmacologically activeDescribing a substance that exhibits a measurable effect on a biological system, such as a cell, tissue...
• PharmacologyThe scientific study of the effects of chemical substances on living systems, including their mechanisms of...
• PharmacophoreAn ensemble of steric and electronic features in a molecule that is necessary to produce a specific...
• Pharyngeal grooveAn external invagination of the ectoderm in a developing vertebrate embryo, located on the outer surface...
• Pharyngeal pouchAn outpocketing of the endodermal lining of the pharynx in a developing vertebrate embryo, positioned...
• PharynxA muscular tube that extends from the base of the skull to the esophagus, serving as a common passageway for...
• PhaseA portion of a system whose chemical composition and physical state are the same throughout, set off from the...
• Phase 0 clinical studiesExploratory studies conducted early in drug development with very limited human exposure to the...
• Phase correctionA computational procedure applied to Fourier transform spectra, especially in nuclear magnetic resonance...
• Phase cyclingA technique in pulsed nuclear magnetic resonance spectroscopy where the phases of radiofrequency pulses and...
• Phase diagramA graphical representation showing the stable phases of a substance or mixture under different conditions of...
• Phase domainA region within a multiphase material that consists of a single, homogeneous phase. These domains are...
• Phase functionA function that describes the angular distribution of scattered radiation from a particle or a volume element...
• Phase I clinical studiesThe initial stage of human testing for a new drug, primarily focusing on safety, dosage range, and...
• Phase I reactionA metabolic transformation of a xenobiotic or endogenous compound that introduces or unmasks a polar...
• Phase II clinical studiesThe second stage of human testing for a new drug, involving a larger group of patients with the target...
• Phase II reactionA metabolic process that involves the conjugation of a xenobiotic or its phase I metabolite with an...
• Phase III clinical studiesLarge-scale clinical trials conducted on hundreds to thousands of patients to confirm the efficacy and...
• Phase III reactionA metabolic process involving the transport of xenobiotic conjugates, which are formed during phase II...
• Phase interactionThe forces and phenomena occurring at the interface between two distinct phases within a multiphase material...
• Phase inversionThe phenomenon in a liquid-liquid extraction system where the dispersed phase and the continuous phase...
• Phase IV clinical studiesPost-marketing surveillance studies conducted after a drug has been approved and released to the market...
• Phase ratioThe volume of mobile phase in a chromatographic column divided by the volume of stationary phase, symbol β, a...
• Phase ruleA thermodynamic relationship, F = C − P + 2, that relates the number of degrees of freedom (F) in a closed...
• Phase separationSplitting of a single homogeneous solid or liquid mixture into two or more phases of different composition...
• Phase transitionA transformation of a thermodynamic system from one phase or state of matter to another, driven by changes in...
• Phase volume ratioA dimensionless ratio equal to the volume of the mobile liquid phase divided by the volume of the stationary...
• Phase-space theoryA statistical theory used in chemical kinetics to predict the product state distributions and reaction rates...
• Phase-transfer catalysisA method that facilitates the reaction between reactants located in different immiscible phases, such as an...
• Phase-transfer event in a dispersed systemThe movement of a chemical species, such as a monomer or radical, from one phase to another within a...
• PhenolatesAnions derived from phenols by the deprotonation of the phenolic hydroxyl group. These species possess a...
• Phenolic polymerA polymer derived from the condensation reaction of phenols with aldehydes, most commonly formaldehyde. These...
• PhenologyThe study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal...
• PhenolsOrganic compounds characterized by a hydroxyl group directly attached to an aromatic hydrocarbon ring. The...
• PhenomeThe complete set of observable traits or characteristics of an organism, resulting from the interaction of...
• Phenomenological equationA macroscopic equation that describes the relationship between fluxes and forces in a system, without...
• Phenonium ionsCarbocations in which a phenyl group participates in stabilizing the positive charge through intramolecular...
• PhenotypeThe observable characteristics or traits of an organism, resulting from the interaction between its genotype...
• Phenotypic screeningA drug discovery approach where compounds are tested for their ability to induce a desired change in cell or...
• PhenoxidesAnions formed by the deprotonation of a phenol, where the hydroxyl proton is removed, leaving a negatively...
• PhenylketonuriaAn inherited metabolic disorder characterized by the inability to metabolize the amino acid phenylalanine...
• PheochromocytomaA rare tumor that develops in the adrenal medulla, leading to the overproduction of catecholamines, primarily...
• PheromoneA chemical substance released by an organism into the environment that affects the behavior or physiology of...
• Philadelphia chromosomeA specific chromosomal abnormality resulting from a reciprocal translocation between chromosome 9 and...
• PhiltrumThe shallow vertical furrow running down the middle of the upper lip from the nose to the lip's edge. It...
• PhocomeliaA congenital malformation characterized by the severe shortening or absence of proximal limbs, resulting in...
• PhononA quantum of vibrational energy in a crystal lattice, analogous to a photon as a quantum of electromagnetic...
• PhonophobiaAn abnormal fear of or aversion to sounds, classed as a specific phobia, in which everyday noises, often loud...
• Phorbol 12-myristate 13-acetateA phorbol diester, originally isolated from croton oil, that mimics diacylglycerol and directly activates...
• PhosphanesA class of phosphorus hydrides and their organic derivatives, formally derived from phosphine (PH3) by...
• Phosphatidic acidsGlycerophospholipids in which two fatty acyl groups are esterified to the sn-1 and sn-2 positions of...
• PhosphazenesCompounds that have a double bond between phosphorus and nitrogen, as in the chains, rings and cages made...
• Phosphine oxidesA class of organophosphorus compounds in which a phosphorus atom carries three organic groups and a terminal...
• PhosphinesOrganic compounds containing a trivalent phosphorus atom bonded to three organic groups, with the general...
• Phosphinic acidsOrganic phosphorus compounds containing a phosphorus atom bonded to two organic groups, one hydroxyl group...
• Phosphinous acidsCompounds of the form R2P-OH, derived from the parent H2POH, in which a trivalent phosphorus atom carries two...
• PhosphoA prefix in biochemical nomenclature, used in place of phosphono, for the phosphoryl group -P(=O)(OH)2...
• PhosphoglyceridesGlycerol-based phospholipids where two fatty acyl groups are esterified to the sn-1 and sn-2 positions of...
• Phospholipase CγAn enzyme that hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate...
• PhospholipidsA class of lipids that are major components of all cell membranes, composed of a phosphate-containing polar...
• Phosphonic acidsOrganic phosphorus compounds with the general formula RP(O)(OH)2, where R represents an organyl group. These...
• PhosphonitrilesInorganic polymers or oligomers containing alternating phosphorus and nitrogen atoms in a ring or chain...
• Phosphonium compoundsOrganic phosphorus compounds featuring a positively charged phosphorus atom bonded to four organic groups or...
• Phosphonium ylidesNeutral dipolar compounds containing a positively charged phosphorus atom directly bonded to a negatively...
• PhosphonoA prefix used in chemical nomenclature to denote the presence of a -P(O)(OH)2 group, derived from phosphonic...
• Phosphonous acidsCompounds of the form R-P(OH)2, derived from the parent HP(OH)2, in which a trivalent phosphorus atom bears...
• PhosphoramidesCompounds obtained from phosphoric acid by replacing one or more of its OH groups with amino or substituted...
• PhosphoranesNeutral pentacoordinate phosphorus compounds containing a central phosphorus atom with five covalently bonded...
• Phosphoranyl radicalsRadical species in which the unpaired electron is formally localized on a phosphorus atom, which is bonded to...
• PhosphorescenceA type of luminescence where energy absorbed by a substance is re-emitted slowly as light. This occurs when...
• Phosphorescence lifetimeThe average time a molecule remains in its excited triplet state before undergoing phosphorescence, which is...
• PhosphoroscopeAn optical instrument designed to measure the phosphorescence lifetime of a sample by mechanically separating...
• Photo- techniqueA prefix for a thermal analysis method in which a sample is deliberately irradiated with light during the...
• Photoacid generatorA compound that produces an acid upon exposure to ultraviolet (UV) or other high-energy radiation. These...
• Photoacoustic detectorA device that measures the acoustic waves generated when a sample absorbs modulated electromagnetic...
• Photoacoustic effectThe generation of an acoustic wave in a material following the absorption of modulated or pulsed...
• Photoacoustic saturationA condition in photoacoustic spectroscopy where the signal no longer increases linearly with increasing...
• Photoacoustic spectroscopyA spectroscopic technique that measures the acoustic waves generated when a sample absorbs modulated or...
• Photoactive compoundA substance that undergoes a chemical or physical change upon exposure to light, leading to a modification of...
• PhotoadsorbateA chemical species that is adsorbed onto a surface as a direct result of exposure to light or other...
• PhotoadsorptionThe adsorption of a substance onto a surface that is induced or enhanced by the absorption of light. This...
• Photoadsorption area numberThe number of molecules of a specific substance that photoadsorb on a unit area of a photocatalyst surface...
• Photoadsorption capacityThe maximal number of entities, whether molecules, atoms or ions, that can be photoadsorbed per regular...
• Photoadsorption centreA specific site on the surface of a material that becomes active for adsorbing a molecule upon electronic...
• Photoadsorption efficiencyThe ratio of the rate of photoadsorption of a substance to the rate of photon incidence on the photocatalyst...
• Photoadsorption fractionThe number of photoadsorbed atoms, molecules or ions divided by the number of regular surface sites available...
• Photoadsorption photonic yieldThe ratio of the maximal, usually initial, rate of photoadsorption of an entity on a surface to the incident...
• Photoadsorption quantum yieldThe number of molecules of a substance that are photoadsorbed onto a surface, divided by the number of...
• Photoaffinity labellingA technique used to identify and characterize biomolecule binding sites by forming a covalent bond between a...
• PhotoallergyAn acquired, delayed-type hypersensitivity reaction of the skin to a chemical substance that becomes...
• Photoassisted catalysisA catalytic reaction in which light is used only to generate the catalyst, for instance by photolysis of a...
• photo-Bergman cyclizationA photochemical reaction involving an enediyne derivative that, upon irradiation, undergoes an intramolecular...
• PhotobiologyThe scientific study of the interactions between light, specifically non-ionizing radiation, and living...
• Photocaged fluorescent moleculesFluorescent molecules whose fluorescence is temporarily suppressed by a covalently attached 'cage' group...
• PhotocarrierA mobile charge carrier, either an electron or a hole, generated within a material upon the absorption of a...
• PhotocatalysisA catalytic process that involves the absorption of light by a catalyst, leading to the formation of an...
• PhotocatalystA substance that absorbs light and, as a result, facilitates or accelerates a chemical reaction without being...
• Photocatalytic active centreA specific site on the surface of a photocatalyst where a chemical reaction is initiated or accelerated by...
• Photocatalytic activityThe rate or extent to which a material catalyzes a chemical reaction under illumination. This activity is...
• Photocatalytic centreA specific location on the surface of a photocatalyst where light-induced chemical reactions take place...
• Photocatalytic efficiencyThe number of product entities formed, or reactant entities consumed, divided by the number of photons...
• Photocatalytic oxidationA chemical process where a substance is oxidized through the action of a photocatalyst under illumination...
• Photochemical aromatic substitutionA type of substitution reaction on an aromatic ring that is initiated or promoted by light. Unlike thermal...
• Photochemical curingA process of hardening or crosslinking a polymeric material through exposure to light, typically ultraviolet...
• Photochemical equivalenceThe principle stating that each molecule undergoing a photochemical reaction absorbs one photon of light...
• Photochemical funnelA region on a potential energy surface where two or more electronic states become degenerate or nearly...
• Photochemical nitrogen extrusionA chemical reaction where a nitrogen molecule (N2) is eliminated from an organic compound upon absorption of...
• Photochemical nucleophile-olefin combination - aromatic substitutionA reaction sequence involving the light-induced combination of a nucleophile and an olefin, followed by an...
• Photochemical reactionA chemical reaction that is initiated by the absorption of light by one or more reactants. The absorbed light...
• Photochemical reaction pathThe detailed sequence of elementary steps that a molecule follows during a photochemical reaction, starting...
• Photochemical smogA type of air pollution formed when sunlight reacts with nitrogen oxides and at least one volatile organic...
• PhotochemistryThe scientific study of chemical reactions that are initiated by the absorption of light by atoms or...
• PhotochirogenesisThe generation of chirality or the induction of enantiomeric excess in a chemical reaction through the use of...
• Photochromic polymerA polymer that reversibly changes its color or optical properties upon exposure to light of a specific...
• PhotochromismA reversible transformation of a chemical species between two forms, induced by electromagnetic radiation...
• photo-Claisen rearrangementA photochemical reaction that is analogous to the thermal Claisen rearrangement, involving the light-induced...
• Photoconducting polymerA polymeric material that exhibits increased electrical conductivity upon exposure to electromagnetic...
• Photoconductive detectorA radiation detector that operates by changing its electrical conductivity upon exposure to electromagnetic...
• PhotoconductivityAn increase in the electrical conductivity of a material caused by absorbing light, which creates mobile...
• Photocontact dermatitisA skin inflammation that develops when a chemical in or on the skin is activated by light, usually...
• PhotocorrosionThe degradation of a material, typically a semiconductor, due to chemical reactions induced by light...
• PhotocrosslinkingThe formation of covalent bonds between polymer chains or between molecules upon irradiation with light. This...
• PhotocurrentAn electric current generated in a material when it absorbs light. This current arises from the movement of...
• Photocurrent yieldThe efficiency with which absorbed photons are converted into electrical current in a photoelectrochemical or...
• PhotocyclizationA photochemical reaction in which a molecule undergoes an intramolecular cyclization, forming a new ring...
• PhotodecarbonylationA photochemical reaction involving the elimination of a carbon monoxide (CO) molecule from an organic...
• PhotodecarboxylationA photochemical reaction in which a carbon dioxide (CO2) molecule is eliminated from a carboxylic acid or its...
• PhotodeconjugationA photochemical reaction where a conjugated system, such as a double bond or a carbonyl group, undergoes a...
• PhotodegradationThe process by which a material undergoes chemical alteration or breakdown due to the absorption of light...
• PhotodesorptionThe process by which molecules adsorbed on a surface are released into the gas phase upon illumination. This...
• Photodesorption quantum yieldThe ratio of the number of molecules desorbed from a surface to the number of photons absorbed by the...
• PhotodetachmentThe loss of an electron by an anion that has absorbed a photon, which leaves behind a neutral atom or...
• PhotodetrappingThe process by which charge carriers, previously immobilized in trapping sites within a material, are...
• PhotodiodeA semiconductor device that converts light into an electrical current. When photons strike the photodiode's...
• Photodiode arrayA linear arrangement of multiple individual photodiodes, typically integrated onto a single semiconductor...
• PhotodissociationThe process by which a chemical compound is broken down into smaller fragments through the absorption of...
• Photodynamic effectThe phenomenon where a substance, known as a photosensitizer, absorbs light energy and then transfers this...
• Photo-elastic polymerA polymer that exhibits birefringence when subjected to mechanical stress, meaning its refractive index...
• Photoelectric attenuation coefficientA measure of the probability that a photon will undergo a photoelectric effect interaction per unit path...
• Photoelectric peakThe peak in a gamma-ray spectrum that corresponds to the full energy deposition of a gamma-ray photon in the...
• Photoelectric work functionThe minimum energy required to remove an electron from a solid surface into a vacuum, overcoming the...
• Photoelectrical effectThe emission of electrons from a material when light shines on it. This effect occurs when photons with...
• PhotoelectrocatalysisA process that combines photocatalysis and electrocatalysis, where light absorption and an applied electric...
• Photoelectrochemical cellAn electrochemical cell where at least one electrode is a semiconductor material that absorbs light to drive...
• Photoelectrochemical etchingA process where a semiconductor material is selectively dissolved or removed from a surface through a...
• PhotoelectrochemistryThe study of chemical reactions that occur at the interface between an electrode and an electrolyte solution...
• PhotoelectrodeAn electrode, typically made of a semiconductor material, that absorbs light and generates charge carriers to...
• Photoelectrolytic cellA type of photoelectrochemical cell where light energy is used to drive a non-spontaneous chemical reaction...
• Photoelectron spectroscopyA surface-sensitive analytical technique that measures the kinetic energy of electrons emitted from a...
• Photoelectron X-ray satellite peaksWeak photoelectron peaks in an XPS spectrum produced when minor characteristic lines of the X-ray anode, such...
• Photoelectron X-ray satellite subtractionA data processing technique used in X-ray photoelectron spectroscopy (XPS) to remove or reduce the...
• Photoelectron yieldThe number of photoelectrons emitted from a material per incident photon of a given energy. This quantity is...
• PhotoelectrosynthesisA light-driven process at an illuminated semiconductor in contact with a liquid, in which photon absorption...
• PhotoemissionThe emission of electrons from a material when it absorbs electromagnetic radiation, such as light or X-rays...
• Photoemissive detectorA type of radiation detector that operates on the principle of the photoelectric effect, where incident...
• PhotoenolisationA phototautomerization in which an excited carbonyl compound abstracts a hydrogen atom from a position gamma...
• PhotoexcitationThe process where an atom, molecule, or ion absorbs a photon, causing an electron to transition from a lower...
• photo-Fries rearrangementA photochemical reaction in which aryl esters or amides, upon irradiation with ultraviolet light, rearrange...
• Photogalvanic cellAn electrochemical cell that generates an electric current when exposed to light, due to light-induced redox...
• Photogenerated catalysisCatalysis in which light is used only to create a catalytically active species, such as a radical, a metal...
• Photogenerated charge carrierA mobile electron or hole created in a material, such as a semiconductor, upon the absorption of a photon...
• Photographic plate recordingA method of detecting and recording ions in mass spectrometry by exposing a photographic emulsion to the ion...
• PhotohydrationA photochemical reaction involving the addition of water across a double bond or to an aromatic system...
• Photoinduced dischargeThe process by which an electrical charge stored on the surface of a photoconductive material is neutralized...
• Photoinduced electron transferThe transfer of an electron between two molecules or within a single molecule, initiated by the absorption of...
• Photoinduced polymerizationA polymerization reaction initiated by the absorption of light, which generates reactive species such as free...
• Photo-induced toxicityThe adverse effects on an organism caused by a chemical substance that becomes toxic only after exposure to...
• PhotoinitiationThe primary step in a photochemical reaction where the absorption of light leads to the formation of reactive...
• PhotoinitiatorA chemical compound that, upon absorption of light, generates reactive species such as free radicals or ions...
• PhotoinjectionThe process where charge carriers are introduced into a material from an external electrode or another...
• PhotoionizationThe process by which an atom or molecule loses an electron upon absorbing a photon with energy greater than...
• Photoionization cross sectionA measure of the probability that an atom or molecule will absorb a photon and subsequently eject an...
• Photoionization detectorA type of gas detector that uses ultraviolet (UV) light to ionize molecules, allowing for their detection and...
• Photo-irritationA non-immunological, acute inflammatory response of the skin to a chemical substance after exposure to light...
• PhotoisomerizationA photochemical reaction where a molecule undergoes a change in its molecular structure to form an isomer...
• PhotolithographyA patterning process that uses light to transfer a geometric design from a photomask to a light-sensitive...
• PhotoluminescenceThe emission of light from a substance that has absorbed photons, causing it to transition to an excited...

1,381 of 13,676 terms in Chemistry terminology (MLC-0109). Request the full dataset.