Line coupling effects in the isotropic Raman spectra of N2: A quantum calculation at room temperature

Franck Thibault (1) , Christian Boulet (2) , Qiancheng Ma (3)

1 IPR - Institut de Physique de Rennes
2 ISMO - Institut des Sciences Moléculaires d'Orsay
3 APAM - Department of Applied Physics and Applied Mathematics [New York]

We present quantum calculations of the relaxation matrix for the Q branch of N2 at room temperature using a recently proposed N2-N2 rigid rotor potential. Close coupling calculations were complemented by coupled states studies at high energies and provide about 10 200 two-body state-to state cross sections from which the needed one-body cross-sections may be obtained. For such temperatures, convergence has to be thoroughly analyzed since such conditions are close to the limit of current computational feasibility. This has been done using complementary calculations based on the energy corrected sudden formalism. Agreement of these quantum predictions with experimental data is good, but the main goal of this work is to provide a benchmark relaxation matrix for testing more approximate methods which remain of a great utility for complex molecular systems at room (and higher) temperatures.

Mots clés: Total energy calculations; Quantum molecular calculations; Linewidths; Raman spectra; Testing procedures

Domaines: Chimie-Physique [physics.chem-ph]

Franck Thibault, Christian Boulet, Qiancheng Ma. Line coupling effects in the isotropic Raman spectra of N2: A quantum calculation at room temperature. Journal of Chemical Physics, 2014, 140 (4), pp.044303. ⟨10.1063/1.4862082⟩. ⟨hal-00971689⟩