Analysis of Rotational and Rovibrational Spectra of SiDF3 in the Ground and v4 = 1 Excited States

Abstract

This paper presents the analysis of the spectra of SiDF3 in its vibrational ground and v4 = 1 states. The pure rotational spectrum of the ground state was measured up to 903 GHz (J" = 65). Rotational, quartic, and sextic centrifugal distortion constants were accurately determined. Furthermore the parameter ‖h3‖ = 7.64(11) × 10−4 Hz was derived from the observation of A1–A2 splittings of six K = 3 lines. The assignment of the v4 = 1 spectrum was performed by combining 140 pure rotational frequencies and more than 2300 rovibrational transitions. Among them, because of the strong (±2, ∓4) interaction, there are more than 90 A1–A2 resolved split transitions between the (l = 0, k = ±3) ground state levels and the (l = ±2, k = ∓1) v4 = 1 levels. Although the v4 band is located at about 994.3 cm−1, the energies of the other fundamental bands are at a distance of more than 140 cm−1. The assumption of the isolated character of the state was confirmed by the small differences between the v4 = 1 state and the ground state parameters and by the possibility of using the D and Q reduction schemes proposed by E. I. Lobodenko, O. N. Sulakshina, V. I. Perevalov, and Vl. G. Tyuterev [J. Mol. Spectrosc. 126, 159–170 (1987)].