Spectra of jet-cooled SO232 and SO234 in systems ã 3B1 and b 3A2–X 1A1: Rotational structure of perturbed b 3A2

Spectra of ã 3B1(ν1ν2ν3)=(110) and (200)–X̃ 1A1(000) of SO232 and SO234 are obtained in a supersonic jet at a resolution 0.015 cm−1. The rotational structures are analyzed for both isotopic species to obtain precise rotational and spin constants. Two new bands at 27 032.222(1) and 27 515.41(1) cm−1 arising from vibronic interaction separately with vibrational state (110) and (200) of ã 3B1 are assigned to transitions to b̃ 3A2(011) and (101). The rotational structure of b̃ 3A2 is observed and analyzed for the first time. The two vibrational states are analyzed to yield effective rotational constants A=1.4348(3), 1.89(3), B=0.3610(3), 0.412(3), and C=0.2689(3), 0.239(3) cm−1, respectively. Then the difference ν1−ν2 of vibrational frequency of b̃ 3A2 is obtained to be 483.19 cm−1. Because of interaction to b̃ 3A2(011) the observed spacing of K stack and spin constants α and β for ã 3B1(110) are smaller whereas the state ã 3B1(200) is relatively unaffected and only spin constants vary significantly.