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Towards the Complete Analysis of the Rotational Spectrum of (CH3)3SnCl



Melanie Schnell, Jon T. Hougen, J U. Grabow


The rotational spectrum of the symmetric top trimethyl tin chloride (CH3)3SnCl has been studied using a pulsed molecular beam Fourier transform microwave spectrometer in the frequency range from 3 to 24 GHz. The spectrum is exceedingly complicated by the internal rotation motions of the three equivalent methyl tops, the high number of Sn- and Cl-isotopes and the quadrupole hyperfine structure of the chlorine nucleus. In this paper, we present the microwave spectrum, ab initio calculations, permutation inversion (PI) group-theoretical considerations, Stark-effect measurements and finally the assignments and fits of the different torsion-rotation species. Based on the Stark-effect measurements, the dipole moment is ? = 3.4980(30) D. Due to ?K = ?1 mixing effects we observe linear Stark-effect behavior and additional K = 0 quadrupole splitting for some K = 0 torsion-rotation transitions in (CH3)3SnCl, which can be group-theoretically explained. The symmetric rotor fit of A1 states leads to an effective B-constant of 1680.040124(50) MHz for the main isotopologue (CH3)3120Sn35Cl. A global fit of 182 K = 0 torsion-rotation transitions yields a V3 torsional barrier of 148.299(54) cm-1.
Journal of Molecular Spectroscopy


chlorine nuclear quadrupole splitting, global least-squeares fit, internal rotation, isotopologs, microwave spectroscopy


Schnell, M. , Hougen, J. and Grabow, J. (2008), Towards the Complete Analysis of the Rotational Spectrum of (CH<sub>3</sub>)<sub>3</sub>SnCl, Journal of Molecular Spectroscopy, [online], (Accessed February 23, 2024)
Created January 6, 2008, Updated October 12, 2021