complete active space self-consistent field second-order perturbation theory (CASPT2)
Theoretical scheme suitable for computations of accurate excitation energies and reaction barriers. In the first step, @E01984@ is taken into account only to a certain extent by using a CASSCF formalism (the so called non-dynamic correlation), whereas the remaining @E01984@ (the so called dynamic correlation) is included through the use of second-order @PT07090@.
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 316 [Terms] [Paper]