SMALL SULFUR CLUSTERS IN THE GAS PHASE: PURE ROTATIONAL SPECTROSCOPY OF $S_{3}$ (THIOZONE) AND $S_{4}$

Abstract

The $C_{2v}$ forms of thiozone, $S_{3}$, and tetrasulfur, $S_{4}$, have been investigated by Fourier transform microwave spectroscopy of a supersonic molecular beam. Both molecules represent the global minima on their respective potential energy surfaces. Besides the parent molecules the $mono-^{34}S$ isotopomers have been investigated in natural abundance. For thiozone, a substantial number of vibrational satellites has been detected in addition. The analysis of the spectroscopic data will be discussed and a comparison to recent high-level quantum chemical calculations at the CCSD(T) level of theory will be given. From a calculation of the cubic force field the rotation-vibration interaction constants have been calculated and the mixed experimental-theoretical $r_{e}$ structures have been obtained.