Calculation of rate constants for vibrational and rotational excitation of the H3+ ion by electron impact

TL;DR

This paper provides theoretical calculations of thermally-averaged rate constants for vibrational and rotational excitation of H3+ ions by electron impact, aiding understanding of astrophysical plasma processes.

Contribution

It introduces multi-channel quantum-defect calculations for rate constants involving rotational and vibrational transitions of H3+ for the first time.

Findings

Rate constants for J<=5 rotational states are computed.

Thermal rates for lowest eight vibrational levels are provided.

Discussion on non-thermal distribution conditions in astrophysics.

Abstract

We present theoretical thermally-averaged rate constants for vibrational and rotational (de-)excitation of the H3+ ion by electron impact. The constants are calculated using the multi-channel quantum-defect approach. The calculation includes processes that involve a change Delta J<=2 in the rotational angular momentum J of H3+. The rate constants are calculated for states with J<=5 for rotational transitions of the H3+ ground vibrational level. The thermal rates for transitions among the lowest eight vibrational levels are also presented, averaged over the rotational structure of the vibrational levels. The conditions for producing non-thermal rotational and vibrational distributions of H3+ in astrophysical environments are discussed.