Boltzmann distribution of nuclear spins

{
  "id": "MLC-T-CHM-001409",
  "term": "Boltzmann distribution of nuclear spins",
  "field": "Chemistry",
  "definition": "The statistical spread of nuclear spins over their energy levels at thermal equilibrium in a magnetic field, in which the lower-energy state holds a slight excess of spins set by the Boltzmann factor. This population excess produces the detectable nuclear magnetic resonance signal. At room temperature the excess is only about 30 parts per million for protons at 9.4 tesla, a proton frequency of 400 MHz.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "energy level"
  ],
  "references": [
    "PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 682 (https://doi.org/10.1515/pac-2019-0203)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/boltzmann-distribution-of-nuclear-spins/"
}