Comprehensive analysis of the FASSST rotational spectrum of S(CN) 2

Abstract

Results are reported of a comprehensive investigation of an almost continuous rotational spectrum of S(CN) 2 recorded over the frequency region 110–374 GHz by means of the FASSST spectroscopic technique. The spectrum was analysed in detail and over 22 000 transitions were assigned in total. Precise, octic order spectroscopic constants in the asymmetric rotor Hamiltonian have been determined for the ground state and 12 different vibrationally excited states of the parent isotopologue, including first excited states of five different normal modes. Three states near 370 cm −1 and four states near 490 cm −1 above the ground state were found to be mutually interacting and were successfully analysed in terms of a triad and a tetrad of coupled states, respectively. Rotational transitions in the 34S, 13C, and 15N isotopologues of S(CN) 2 have also been assigned and fitted, and newly determined rotational constants were used to derive the r m ( 1 ) geometry of the molecule. The complex multistate analysis of the spectrum was carried out with the newly developed AABS software package for Assignment and Analysis of Broadband Spectra.