title: Ab initio floating occupation molecular orbital-complete active space configuration interaction: an efficient approximation to CASSCF.
abstract: We have implemented a complete active space configuration interaction method (CASCI) based on floating occupation molecular orbitals (FOMOs) at the ab initio level. The performance of this FOMO-CASCI method was investigated for potential applications in photochemistry and photodynamics. We found that FOMO-CASCI often represents a good approximation to the state-averaged complete active space self-consistent field (SA-CASSCF) method. FOMO-CASCI is therefore an attractive alternative for use in ab initio photodynamics. The method is more efficient and more stable than SA-CASSCF. We also discuss some problematic cases for the FOMO-CASCI approach. Possible extensions of the FOMO-CASCI approach are discussed briefly.
authors.affiliation: Department of Physical Chemistry, Institute of Chemical Technology, Prague, 166 28 Prague 6, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Slavícek
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Martínez