Complete active space self-consistent field second-order perturbation theory

{
  "id": "MLC-T-CHM-002319",
  "term": "Complete active space self-consistent field second-order perturbation theory",
  "field": "Chemistry",
  "definition": "A multi-reference method in computational chemistry that adds dynamic electron correlation to a complete active space self-consistent field (CASSCF) wavefunction. It uses second-order perturbation theory, with the CASSCF wavefunction as the zeroth-order reference, to account for electron correlation effects outside the active space. This approach provides a more accurate description of electronic energies, particularly for excited states and reaction pathways.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "complete active space self-consistent field",
    "electron correlation",
    "perturbation theory"
  ],
  "references": [
    "PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 316 (https://doi.org/10.1351/pac200779030293)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/complete-active-space-self-consistent-field-second-order-perturbation-theory/"
}