# The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened ν _{1} and pure rotational bands of NH _{3}

## Abstract

Line mixing effects have been calculated in the ν _{1} parallel band of self-broadened NH _{3}. The theoretical approach is an extension of a semi-classical model to symmetric-top molecules with inversion symmetry developed in the companion paper [Q. Ma and C. Boulet, J. Chem. Phys. 144, 224303 (2016)]. This model takes into account line coupling effects and hence enables the calculation of the entire relaxation matrix. A detailed analysis of the various coupling mechanisms is carried out for Q and R inversion doublets. The model has been applied to the calculation of the shape of the Q branch and of some R manifolds for which an obvious signature of line mixing effects has been experimentally demonstrated. Comparisons with measurements show that the present formalism leads to an accurate prediction of the available experimental line shapes. Discrepancies between the experimental and theoretical sets of first order mixing parameters are discussed as well as some extensions of both theory and experiment.

- Authors:

- Columbia Univ., New York, NY (United States)
- Univ. Paris-Saclay, Gif-sur-Yvette (France)

- Publication Date:

- Research Org.:
- Columbia Univ., New York, NY (United States)

- Sponsoring Org.:
- National Science Foundation (NSF); USDOE

- OSTI Identifier:
- 1418594

- Grant/Contract Number:
- AC02-05CH11231; NSF-1501297

- Resource Type:
- Journal Article: Accepted Manuscript

- Journal Name:
- Journal of Chemical Physics

- Additional Journal Information:
- Journal Volume: 144; Journal Issue: 22; Journal ID: ISSN 0021-9606

- Publisher:
- American Institute of Physics (AIP)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

### Citation Formats

```
Ma, Q., and Boulet, C.
```*The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened ν1 and pure rotational bands of NH3*. United States: N. p., 2016.
Web. doi:10.1063/1.4952995.

```
Ma, Q., & Boulet, C.
```*The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened ν1 and pure rotational bands of NH3*. United States. doi:10.1063/1.4952995.

```
Ma, Q., and Boulet, C. Tue .
"The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened ν1 and pure rotational bands of NH3". United States.
doi:10.1063/1.4952995. https://www.osti.gov/servlets/purl/1418594.
```

```
@article{osti_1418594,
```

title = {The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened ν1 and pure rotational bands of NH3},

author = {Ma, Q. and Boulet, C.},

abstractNote = {Line mixing effects have been calculated in the ν1 parallel band of self-broadened NH3. The theoretical approach is an extension of a semi-classical model to symmetric-top molecules with inversion symmetry developed in the companion paper [Q. Ma and C. Boulet, J. Chem. Phys. 144, 224303 (2016)]. This model takes into account line coupling effects and hence enables the calculation of the entire relaxation matrix. A detailed analysis of the various coupling mechanisms is carried out for Q and R inversion doublets. The model has been applied to the calculation of the shape of the Q branch and of some R manifolds for which an obvious signature of line mixing effects has been experimentally demonstrated. Comparisons with measurements show that the present formalism leads to an accurate prediction of the available experimental line shapes. Discrepancies between the experimental and theoretical sets of first order mixing parameters are discussed as well as some extensions of both theory and experiment.},

doi = {10.1063/1.4952995},

journal = {Journal of Chemical Physics},

number = 22,

volume = 144,

place = {United States},

year = {Tue Jun 14 00:00:00 EDT 2016},

month = {Tue Jun 14 00:00:00 EDT 2016}

}

*Citation information provided by*

Web of Science

Web of Science

Works referenced in this record:

##
The HITRAN2012 molecular spectroscopic database

journal, November 2013

- Rothman, L. S.; Gordon, I. E.; Babikov, Y.
- Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 130, p. 4-50