Total Absorption Cross Section for UV Excitation of Sulfur Monoxide

In a new study on sulfur monoxide, new ab initio potential energy curves are developed for excited states A³Π, B³Σ^-, C³Π, and C'³Π and for three states that are unassigned in the literature, which we numerically name 3³Σ^-, 4³Π, and 5³Π. All these excited states have allowed transitions from ground state, X³Σ^-. The ab initio calculations were performed using the MRCI-F12+Q/aug-cc-pV(5+d)Z level of theory implemented in MOLPRO2015. On the basis of close-coupling R-matrix theory, fine structure absorption cross sections of isotopically substituted sulfur monoxide are calculated for wavelengths of 190-300 nm. The spectra are shown at the highest possible resolution (FWHH ≈ 0.15-0.18 cm^-1) for reference and future studies. The effects of self-shielding and possible mutual shielding are discussed.