Zero-order B-1(1)(n,O,O) vibrational levels of sulfur dioxide

摘要

More than 100 single vibronic level fluorescence spectra of SO2 throughout the 30 400-34 230 cm(-1) spectral region were selectively excited and recorded in crossed supersonic jet and laser beams under conditions of cold rotational temperatures. It was found that the vibronic origins can be grouped into 5 overlapping regions based on identical Franck-Condon patterns of the (X) over tilde A(1)(n,0,0) progressions. The spacing between the centers of these regions was found to range between 572 cm(-1) and 647 cm(-1) as opposed to the previously estimated value of 690 cm(-1). The onset of the B-1(1) state in the vibronic coupling was found to be at the 30 553 cm(-1) band, which is below the previously reported threshold energy by 220 cm(-1). The results provide qualitative verification of the multilevel coupling mechanism proposed by Kullmer and Demtroder [Chem. Phys. 92, 323 (1985)]. (C) 1998 American Institute of Physics. [S0021-9606(98)01533-5]. [References: 8]