Absorption spectra of SO + in the ultraviolet region

The potential energy curves (PECs), transition dipole moments (TDMs), spectroscopic constants, and spin--orbit coupling (SOC) matrix elements for eight doublet states (X 2 Π$, A^ 2 Π, 1^ 2 Φ, C^ 2 Π, 1^ 2 Δ, B^ 2 Σ^ - , 1^ 2 Σ^ + , and 2^ 2 Σ^ + ) and two quartet states (a^ 4 Π and b^ 4 Σ^ - ) of the sulfur monoxide cation were calculated using the multireference configuration interaction (MRCI) method. Furthermore, the PECs of the X^ 2 Π and A^ 2 Π states were refined by fitting to the experimentally measured vibrational energy levels. Based on these data, the absorption cross sections arising from the A^ 2 Π--X^ 2 Π transition within the 30,000--50,000 cm^-1 range were simulated, and a comprehensive spectral analysis was performed. Moreover, the absorption cross sections for a total of six 2 Π--X^ 2 Π, B^ 2 Σ^ - --X^ 2 Π, C^ 2 Π--X^ 2 Π, 2^ 2 Σ^ + --X^ 2 Π, 1^ 2 Σ^ + --X^ 2 Π, and 1^ 2 Δ--X^ 2 Π---were computed to simulate the absorption spectra of SO$^ + in cosmic atmospheres. It is expected that the spectroscopic data presented in this work will facilitate the characterization of exoplanet atmospheres in future observational missions.