A CASSCF-MRCI study of the electronic excited states of FClO and FOCl

Abstract

The potential energy curves for the low-lying excited states of FClO and FOCl have been computed using the complete active space self-consistent field (CASSCF) with cc-pVTZ basis sets. The vertical excitation energies for the excited states were calculated using the multireference configuration interaction (MRCI) method with cc-pVTZ and cc-pVTZ+sp basis sets. The vertical excitation energies were also obtained using the EOM-CCSD (equation of motion-coupled-cluster single double) method with cc-pVTZ basis sets. Results show that Rydberg character is not present in the excited states studied here for both FClO and FOCl. For FClO, all the excited states studied are repulsive along the F–Cl coordinate, but some of the excited states are bound along the Cl–O coordinate. For FOCl, all the excited states studied are dissociative along both the F–O and O–Cl coordinates.