TY - JOUR

T1 - Towards the complete analysis of the rotational spectrum of (CH3)3SnCl

AU - Schnell, Melanie

AU - Hougen, Jon T.

AU - Grabow, Jens Uwe

PY - 2008/9

Y1 - 2008/9

N2 - 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 K = 0 assignments and fits of the different torsion-rotation species. Based on the Stark-effect measurements, the dipole moment is μ = 3.4980(30) D. Due to Δ K = ± 1-mixing effects we observe linear Stark-effect behavior and additional quadrupole splitting for some K = 0 torsion-rotation transitions in (CH3)3SnCl, which can be group-theoretically explained. The symmetric rotor fit of A1 and A2 torsion-rotation states leads to an effective B-constant of 1680.040124(92) MHz for the main isotopologue (CH3)3120Sn35Cl. A global fit of 182 K = 0 torsion-rotation transitions yields a V3 torsional barrier of 1.774(6) kJ.

AB - 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 K = 0 assignments and fits of the different torsion-rotation species. Based on the Stark-effect measurements, the dipole moment is μ = 3.4980(30) D. Due to Δ K = ± 1-mixing effects we observe linear Stark-effect behavior and additional quadrupole splitting for some K = 0 torsion-rotation transitions in (CH3)3SnCl, which can be group-theoretically explained. The symmetric rotor fit of A1 and A2 torsion-rotation states leads to an effective B-constant of 1680.040124(92) MHz for the main isotopologue (CH3)3120Sn35Cl. A global fit of 182 K = 0 torsion-rotation transitions yields a V3 torsional barrier of 1.774(6) kJ.

KW - Anomalous hyperfine splittings

KW - Equivalent methyl tops

KW - Fourier transform microwave spectroscopy

KW - Internal rotation barrier

KW - Permutation-inversion group theory

KW - Stark effect

UR - http://www.scopus.com/inward/record.url?scp=50549099498&partnerID=8YFLogxK

U2 - 10.1016/j.jms.2008.01.007

DO - 10.1016/j.jms.2008.01.007

M3 - Article

AN - SCOPUS:50549099498

VL - 251

SP - 38

EP - 55

JO - Journal of molecular spectroscopy

JF - Journal of molecular spectroscopy

SN - 0022-2852

IS - 1-2

ER -