The rotation-torsion spectrum of doubly deuterated methanol cd2hoh

Coudert, L.H.

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Description

Title

The rotation-torsion spectrum of doubly deuterated methanol cd2hoh

Author(s)

Coudert, L.H.

Contributor(s)

• Kwabia Tchana, F.
• Motiyenko, R. A.
• Margulès, L.

Issue Date

2020-06-22

Keyword(s)

Mini-symposium: Large Amplitude Motions

Abstract

Doubly deuterated methanol CD$_2$HOH is a non-rigid molecule displaying internal rotation of its asymmetrical CD$_2$H methyl group. Like the isotopic species of methanol with a symmetrical CH$_3$ or CD$_3$ group, it displays a strong rotation-torsion Coriolis coupling. Unlike these species, it also displays a dependence of its generalized inertia tensor on the angle of internal rotation. Its complicated rotation-torsion spectrum was investigated in the microwave,\footnote{Liu \& Quade, {\em J.\ Mol.\ Spectrosc.}~{\bf 146} (1991) 252; Su, Liu, \& Quade, {\em J.\ Mol.\ Spectrosc.}~{\bf 149} (1991) 557; Quade, Liu, Mukhopadhyay, \& Su, {\em J.\ Mol.\ Spectrosc.}~{\bf 192} (1998) 378; Su \& Quade, {\em J.\ Chem.\ Phys.}~{\bf 90} (1989) 1396} submillimeter-wave,\footnotetext[2]{Ndao, Tchana, Coudert, Motiyenko, Margul\`es, Barros, Manceron, \& Roy, {\em J.\ Mol.\ Spectrosc.}~{\bf 326} (2015) 136}\footnotetext[3]{Mukhopadhyay, {\em Inf.\ Phys.\ Tech.}~{\bf 75} (2016) 139; {\em ibid.}~{\bf 76} (2016) 116}$^{b,c}$ terahertz,$^b$ and FIR$^{b,c}$ domains. Although more than 3000 transitions have been assigned so far, no global analysis, like the one performed for the similar species CH$_2$DOH,\footnotetext[4]{Coudert, Zemouli, Motiyenko, Margul\`es, \& Klee, {\em J.\ Chem.\ Phys.}~{\bf 140} (2014) 064307}$^d$ has been carried out. In this talk, new assignments in the terahertz and FIR spectra of CD$_2$HOH will be reported. Parallel and perpendicular transitions, characterized by a higher $K$-value than in our previous investigation,$^b$ could be identified up to $J=35$ for the three lowest lying torsional states. Using the theoretical approach developed for CH$_2$DOH,$^d$ a global analysis of the available high-resolution data has been attempted in order to check the new assignments and to retrieve spectroscopic parameters such as those describing the hindering potential and the generalized inertia tensor.\footnotetext[5]{Liu \& Quade, {\em J.\ Mol.\ Spectrosc.}~{\bf 146} (1991) 238; El Hilali, Coudert, Konov, \& Klee, {\em J.\ Chem.\ Phys.}~{\bf 135} (2011) 194309}$^e$ So far, this global analysis has been restricted to transitions with $K\geq4$ as rotation-torsion levels with $K<4$ are affected by strong rotation-torsion couplings and cannot be properly modeled. Hopefully this issue will be dealt with by the time of the Symposium.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

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http://hdl.handle.net/2142/107438

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