Sub-Doppler High-Resolution Spectroscopy of 15V Band of CS2 and the Zeeman Effect

Excitation spectra and the Zeeman spectra of CS 2 in the region of 31320-31445 cm -1 were measured with sub-Doppler resolution. Observed rotational lines were classified to 14 series of lines (vibronic bands) and were named by the wavenumbers of their band origins. The 31344.9 band is the strongest one and is assigned as the main band of theV 1 B 2 0 v 20 ( K = 0 )–X 1∑ g + 00 0 0 transition. Most of the extra bands may be allowed by the vibronic interaction between theV 1 B 2 0 v 20( K = 0 )level and singlet levels, which are mostly high vibrational levels of the 1A 1 ( X 1∑ g + ) state. The Zeeman splittings are observed for several lines in almost all bands. These may be originating from the spin-orbit interaction between the rotational levels, which have accidentally nearly the same energy, of the 1A 1 ( X 1∑ g + ) state and the 3A 2 ( 3Δ u ) or/and 3B 2 ( 3Δ u ) state.