Electron collisions with H₂ from electronically excited states using the R-matrix method

Electron collisions with H₂ are important for the semiconductor plasma industry, magnetically confined fusion reactors and astrophysical modelling. In previous work [1], R-matrix calculations for electron impact electronic excitation of H₂ from its ground state were presented. The results were in agreement with recent experimental data and accurate theoretical calculations obtained by the Molecular Convergent Close-Coupling approach. This presentation covers our latest work [2] where the R-matrix approach has been used to produce integrated cross-sections for electron collisions with H₂ from an initially excited state. Our calculations suggest that previous theoretical results overestimate the cross-sections by as much as a factor of 5 for certain transitions. This work has been made possible by recent developments in the UKRMol+ code [3] which now supports B-spline type orbitals for use in the continuum. In this work we required a radius of 100 Bohr in order to support the extremely diffuse, highly-excited target states that were of interest. Cross-sections for the first 12 excited states are discussed with a focus on the metastable triplet a and c states.

[1] T. Meltzer et al., JPhysB 53, 145204 (2020).

[2] T. Meltzer et al., JPhysB 53, 245203 (2020).

[3] Z. Mašín et al., CPC 249, 107092 (2020).