Publication Abstracts

Ma and Boulet 2016

Ma, Q., and C. Boulet, 2016: The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened v1 and pure rotational bands of NH3. J. Chem. Phys, 144, no. 22, 224303, doi:10.1063/1.4952995.

The Robert-Bonamy formalism has been commonly used to calculate half-widths and shifts of spectral lines for decades. This formalism is based on several approximations. Among them, two have not been fully addressed: the isolated line approximation and the neglect of coupling between the translational and internal motions. Recently, we have shown that the isolated line approximation is not necessary in developing semi-classical line shape theories. Based on this progress, we have been able to develop a new formalism that enables not only to reduce uncertainties on calculated half-widths and shifts, but also to model line mixing effects on spectra starting from the knowledge of the intermolecular potential. In our previous studies, the new formalism had been applied to linear and asymmetric-top molecules. In the present study, the method has been extended to symmetric-top molecules with inversion symmetry. As expected, the inversion splitting induces a complete failure of the isolated line approximation. We have calculated the complex relaxation matrices of self-broadened NH3. The half-widths and shifts in the v1 and the pure rotational bands are reported in the present paper. When compared with measurements, the calculated half-widths match the experimental data very well, since the inapplicable isolated line approximation has been removed. With respect to the shifts, only qualitative results are obtained and discussed. Calculated off-diagonal elements of the relaxation matrix and a comparison with the observed line mixing effects are reported in the companion paper (Paper II).

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BibTeX Citation

@article{ma01210r,
  author={Ma, Q. and Boulet, C.},
  title={The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened v1 and pure rotational bands of NH3},
  year={2016},
  journal={J. Chem. Phys},
  volume={144},
  number={22},
  pages={224303},
  doi={10.1063/1.4952995},
}

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RIS Citation

TY  - JOUR
ID  - ma01210r
AU  - Ma, Q.
AU  - Boulet, C.
PY  - 2016
TI  - The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened v1 and pure rotational bands of NH3
JA  - J. Chem. Phys
VL  - 144
IS  - 22
SP  - 224303
DO  - 10.1063/1.4952995
ER  -

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