Algebraic approach for the calculation of polyatomic Franck–Condon factors.: Application to the vibronically resolved emission spectrum of S2O

Emission spectra obtained from jet-cooled disulfur monoxide (S2O) molecules have been interpreted quantitatively by means of a U(2) Lie algebraic theory. Fluorescence accompanying selective excitation of the S2O C̃ 1A′←X̃ 1A′ (π∗←π) absorption system was dispersed under modest resolution, thereby permitting vibrational assignment of ground-state levels possessing up to 20 quanta of the ν2 S–S stretching mode. Aside from providing a convenient framework for analysis of recorded energy patterns, the algebraic treatment allows for straightforward calculation of multidimensional Franck–Condon factors and corresponding transition intensities. The emerging picture of S2O vibrational dynamics suggests that the X̃ 1A′ potential surface is substantially more `localʹ in character than the C̃ 1A′ manifold.