Characteristic patterns in microwave spectra of quasi-symmetric top molecules of the WH 3XYZ type

Abstract

Characteristic patterns in microwave spectra of quasi-symmetric top molecules of the WH 3 XYZ type are discussed in terms of the quasi-symmetric top model accounting for the large-amplitude WXY bending motion, and internal and overall rotation. The molecules SiH 3NCS, SiH 3NCO, CH 3NCS, CH 3NCO, and CH 3SCN, exemplifying the symmetric, quasi-symmetric, and asymmetric top molecules, are considered. The correlation parameter γ v is defined to quantify the position of a WH 3 XYZ molecule between the two symmetric and asymmetric top limiting cases. The quasi-symmetric top model is compared to the usual approach to the rotational-vibrational problem of symmetric top molecules.