Ro-vibrational relaxation of HCN in collisions with He: Rigid bender treatment of the bending-rotation interaction

TL;DR

This paper introduces a new theoretical method for accurately modeling the ro-vibrational relaxation of HCN in collisions with He, explicitly treating bending-rotation coupling within the rigid bender approximation at the Close Coupling level.

Contribution

The paper develops a novel RBCC method that exactly accounts for rotation-bending coupling in atom-rigid bender collisions, improving upon previous approximations.

Findings

The new method provides more accurate cross sections for rotational transitions.

Comparison shows the rigid bender approximation's validity varies with conditions.

Results highlight differences between exact and averaged approximation methods.

Abstract

We present a new theoretical method to treat atom-rigid bender inelastic collisions at the Close Coupling level (RBCC) in the space fixed frame. The coupling between rotation and bending is treated exactly within the rigid bender approximation and we obtain the cross section for the rotational transition between levels belonging to different bending levels. The results of this approach are compared with those obtained when using the rigid bender averaged approximation (RBAA) introduced in our previous work dedicated to this system. We discuss the validity of this approximation and of the previous studies based on rigid linear HCN.