ExoMol photodissociation cross-sections – V. Photodissociation rates of the SO radical

ABSTRACT Rovibronic state-resolved predissociation rates and temperature-dependent photodissociation cross-sections are computed for sulphur monoxide ($^{32}$S$^{16}$O). We present a refinement of the ExoMol SOLIS spectroscopic model using empirical (MARVEL) rovibronic energy levels for the $B\, {}^{3}\Sigma ^{-}$ and $C\, {}^{3}\Pi$ states. To accurately model predissociation, the lowest quintet state, $(1)\, {}^{5}\Pi$, and its associated couplings are incorporated, with line widths determined via a stabilization approach. The total photodissociation cross-sections account for both direct photoabsorption and predissociation. To ensure completeness, a short-wavelength ‘top-up’ from the Leiden data base is integrated for regions where the current model does not capture specific predissociation coupling mechanisms. Our results demonstrate that SO photodissociation rates are highly sensitive to temperature; for instance, under a 3000 K blackbody radiation field, rates vary by three orders of magnitude across the molecular temperature range studied. The new SOLUVIS cross-sections are available via the ExoPhoto data base https://www.exomol.com/ExoPhoto.