The objective of this work is to derive approximate rovibrational selection rules for the interaction-induced molecular absorption in dipole-less polyatomic molecules. Taking a combination ${\nu }_2+{\nu }_3$ band in the ${\mathrm{CO}}_2$ molecule as an example, we show that selection rules $\mathrm{\Delta }J=\pm 1$ are allowed in collision-induced absorption (CIA) along with conventional selection rules $\mathrm{\Delta }J=0,\pm 2$ characteristic for CIA in homonuclear diatomics. The basis of that condition relates to the combined effect of the anisotropy of an external electric perturbation and the anharmonicity of the vibrations.

• Received 28 May 2020
• Accepted 13 July 2020

DOI:https://doi.org/10.1103/PhysRevA.102.023104