Determination of photodissociation and radiative association cross sections from the same time-dependent calculation

TL;DR

This paper discusses the challenges in calculating photodissociation and radiative association cross sections using a unified time-dependent wavepacket approach, demonstrating their computation for HeH+ and deriving related rate constants.

Contribution

It presents a method to compute both photodissociation and radiative association cross sections from a single time-dependent wavepacket calculation, highlighting associated difficulties.

Findings

Calculated photodissociation cross sections for HeH+ vibrational levels.

Extracted radiative association cross sections from the same calculations.

Determined rate constants for photodissociation and radiative association.

Abstract

We illustrate some of the difficulties that may be encountered when computing photodissociation and radiative association cross sections from the same time-dependent approach based on wavepacket propagation. The total and partial photodissociation cross sections from the thirty-three vibrational levels of the b triplet {\Sigma}+ state of HeH+ towards the 9 other triplet {\Sigma}+ and 6 triplet {\Pi} n = 2, 3 higher-lying electronic states are calculated. The corresponding radiative association cross sections are extracted from the same calculations, and the photodissociation and radiative association rate constants are determined.