An a b i n i t i o calculation of the zero-field splitting parameters of the 3A′′ state of formaldehyde

Abstract

The spin dipole–dipole and spin–orbit contributions to the zero-field splitting of the 3A″ state of formaldehyde have been evaluated at the excited state experimental geometry. Ab initio CI wave functions were generated from a Dunning double zeta plus polarization basis set using 3A″ rhf orbitals. Twelve states of each symmetry were used to evaluate the second-order spin–orbit effect. The resulting values of D and E were 0.19 and 0.03 cm−1 with the principal magnetic axes rotated 36° from the CO bond. The values of α and β relative to the inertial axes were calculated to be 0.03 and 0.01 cm−1 compared to the experimental values of 0.05±0.01 and 0.02±0.02 cm−1.