ab initio frame transformation calculations of direct and indirect dissociative recombination rates of HeH+ + e-

TL;DR

This study uses ab initio quantum defect calculations and frame transformation techniques to accurately compute dissociative recombination rates of HeH+ with electrons across a wide energy spectrum, aligning well with experimental data.

Contribution

It introduces a combined ab initio and frame transformation approach to accurately model both direct and indirect dissociative recombination processes of HeH+.

Findings

Good agreement with experimental recombination rates

Method effectively captures low-energy autoionization effects

Method reproduces high-energy Rydberg state contributions

Abstract

The HeH$^+$ cation undergoes dissociative recombination with a free electron to produce neutral He and H fragments. We present calculations using ab initio quantum defects and Fano's rovibrational frame transformation technique, along with the methodology of PRL 89, 263003 (2002), to obtain the recombination rate both in the low-energy (1-300 meV) and high-energy (ca. 0.6 hartree) regions. We obtain very good agreement with experimental results, demonstrating that this relatively simple method is able to reproduce observed rates for both indirect dissociative recombination, driven by rovibrationally autoionizing states in the low-energy region, and direct dissociative recombination, driven by electronically autoionizing Rydberg states attached to higher-energy excited cation channels.