FIRST ASSIGNMENT OF SEVERAL TORSIONAL BANDS OF CH$_2$DOH
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Date
2007
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Although the torsional spectrum of the isotopic species of methanol with a symmetrical CH$_3$ or CD$_3$ methyl group has been studied in great details, almost no investigations have been carried out on partially deuterated species of methanol, like CH$_2$DOH or CD$_2$HOH, with an asymmetrical CH$_2$D or CD$_2$H methyl group. This stems from the fact that these partially deuterated species of methanol require a complicated theoretical treatment} {\bf 38,} 540 (1963).} in order to compute their rotation-torsion energy levels and that they display a dense far infrared torsional spectrum} (2002) and Mukhopadhyay, Perry, Lock, and Klee, 57th International Symposium on Molecular Spectroscopy, paper {\bf RH07} (2002).} difficult to assign. With a view toward understanding this spectrum, a theoretical calculation of the rotation-torsion energy levels of CH$_2$DOH has been undertaken aided by {\em ab initio} calculations. This approach accounts for the complicated torsion-rotation interaction displayed by this molecule and for the fact that, due to the low symmetry of the CH$_2$D methyl group, the inertia tensor is strongly dependent on the torsional angle of rotation. In the theoretical approach, this angle is treated as an active coordinate} {\bf 116,} 8560 (2002).} and matrix elements of the kinetic energy part of the Hamiltonian, involving the inertia tensor, are calculated using Gaussian quadrature.}i\'c, {\em J.\ Chem.\ Phys.} {\bf 87,} 408 (1987).} Rotation-torsion energy levels are obtained using a potential energy function retrieved through {\em ab initio} calculations. In the paper, a calculated rotation-torsion spectrum will be presented and compared to the experimental one, recorded in Gie\ss en. It will be shown that this allows us to assign about 50 torsional bands.
Description
Author Institution: LISA, CNRS/Universites Paris 12 et 7, 61 Avenue du; General de Gaulle, 94010 Creteil, France; Laboratoire de Chimie Physique,; Unite mixte du C.N.R.S.\ et de l'Universite Paris-Sud,; Bat. 490, Universite Paris-Sud, 91405 Orsay Cedex, France; Physikalisch-Chemisches Institut, Justus-Liebig-Universitat; Gie\ss en, 35392 Gie\ss en, Germany