Algebraic approach for the calculation of polyatomic Franck–Condon factors: application to the vibronically resolved absorption spectrum of disulfur monoxide (S2O)

Cavity ring-down spectroscopy (CRDS) has been employed to probe the C̃ 1A′←X̃ 1A′ (π*←π) absorption system of jet-cooled disulfur monoxide (S2O) molecules. Vibronically resolved features possessing up to 8 quanta of excitation in the ν2′ S–S stretching mode of the C̃ state have been characterized, with the onset of rapid predissociation for v2′⩾4 being manifest in the widths of band contours. Measured vibronic intensities are in good accord with predictions derived from a Lie algebraic (or vibron) treatment of Franck–Condon factors for the corresponding S2O emission spectrum.