# Accurate first-principles calculations for {sup 12}CH{sub 3}D infrared spectra from isotopic and symmetry transformations

## Abstract

Accurate variational high-resolution spectra calculations in the range 0-8000 cm{sup −1} are reported for the first time for the monodeutered methane ({sup 12}CH{sub 3}D). Global calculations were performed by using recent ab initio surfaces for line positions and line intensities derived from the main isotopologue {sup 12}CH{sub 4}. Calculation of excited vibrational levels and high-J rovibrational states is described by using the normal mode Eckart-Watson Hamiltonian combined with irreducible tensor formalism and appropriate numerical procedures for solving the quantum nuclear motion problem. The isotopic H→D substitution is studied in details by means of symmetry and nonlinear normal mode coordinate transformations. Theoretical spectra predictions are given up to J = 25 and compared with the HITRAN 2012 database representing a compilation of line lists derived from analyses of experimental spectra. The results are in very good agreement with available empirical data suggesting that a large number of yet unassigned lines in observed spectra could be identified and modeled using the present approach.

- Authors:

- Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 6089, BP 1039, F-51687, Reims Cedex 2 (France)
- Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, SB RAS, 634055 Tomsk (Russian Federation)
- (Russian Federation)

- Publication Date:

- OSTI Identifier:
- 22419944

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; HAMILTONIANS; INFRARED SPECTRA; METHANE; SURFACES

### Citation Formats

```
Rey, Michaël, E-mail: michael.rey@univ-reims.fr, Tyuterev, Vladimir G., Nikitin, Andrei V., and Tomsk State University, 36 Lenin Avenue, 634050 Tomsk.
```*Accurate first-principles calculations for {sup 12}CH{sub 3}D infrared spectra from isotopic and symmetry transformations*. United States: N. p., 2014.
Web. doi:10.1063/1.4890956.

```
Rey, Michaël, E-mail: michael.rey@univ-reims.fr, Tyuterev, Vladimir G., Nikitin, Andrei V., & Tomsk State University, 36 Lenin Avenue, 634050 Tomsk.
```*Accurate first-principles calculations for {sup 12}CH{sub 3}D infrared spectra from isotopic and symmetry transformations*. United States. doi:10.1063/1.4890956.

```
Rey, Michaël, E-mail: michael.rey@univ-reims.fr, Tyuterev, Vladimir G., Nikitin, Andrei V., and Tomsk State University, 36 Lenin Avenue, 634050 Tomsk. Mon .
"Accurate first-principles calculations for {sup 12}CH{sub 3}D infrared spectra from isotopic and symmetry transformations". United States.
doi:10.1063/1.4890956.
```

```
@article{osti_22419944,
```

title = {Accurate first-principles calculations for {sup 12}CH{sub 3}D infrared spectra from isotopic and symmetry transformations},

author = {Rey, Michaël, E-mail: michael.rey@univ-reims.fr and Tyuterev, Vladimir G. and Nikitin, Andrei V. and Tomsk State University, 36 Lenin Avenue, 634050 Tomsk},

abstractNote = {Accurate variational high-resolution spectra calculations in the range 0-8000 cm{sup −1} are reported for the first time for the monodeutered methane ({sup 12}CH{sub 3}D). Global calculations were performed by using recent ab initio surfaces for line positions and line intensities derived from the main isotopologue {sup 12}CH{sub 4}. Calculation of excited vibrational levels and high-J rovibrational states is described by using the normal mode Eckart-Watson Hamiltonian combined with irreducible tensor formalism and appropriate numerical procedures for solving the quantum nuclear motion problem. The isotopic H→D substitution is studied in details by means of symmetry and nonlinear normal mode coordinate transformations. Theoretical spectra predictions are given up to J = 25 and compared with the HITRAN 2012 database representing a compilation of line lists derived from analyses of experimental spectra. The results are in very good agreement with available empirical data suggesting that a large number of yet unassigned lines in observed spectra could be identified and modeled using the present approach.},

doi = {10.1063/1.4890956},

journal = {Journal of Chemical Physics},

number = 4,

volume = 141,

place = {United States},

year = {Mon Jul 28 00:00:00 EDT 2014},

month = {Mon Jul 28 00:00:00 EDT 2014}

}