Global analysis of pure-rotational spectra in both the vt = 0 and vt = 1 torsional states of CD3SH

Abstract

The CD3SH molecule, a multiply deuterated isotopologue of methyl mercaptan, can be detected in the interstellar medium with the aid of new high-sensitivity telescopes. Following our previous microwave studies on the ground and first torsional states (J. Mol. Spectrosc. 337(2017) 32–36 and J. Mol. Struc. 1217(2020) 128339), we performed a global analysis for both vt = 0 and vt = 1 torsional states. In this study, 354 transitions (119 (A species) and 76 (E species) in the vt = 0 state and 67 (A species) and 92 (E species) in the vt = 1 state) were newly assigned in addition to the previous assignments. A total of 2130 transition frequencies were analyzed by the least-squares-method using the pseudo-principal axis method (pseudo-PAM) Hamiltonian. Forty-eight parameters consisting of rotational, centrifugal distortion, and internal rotational constants, and centrifugal distortion parameters related to pnJzm terms with n + m = 4 were determined. The last terms will be discussed from a new perspective.