Population of ground and lowest excited states of Sulfur via the dissociative recombination of SH+ in the diffuse interstellar medium

TL;DR

This study extends previous work on the dissociative recombination of SH+ by including new quantum chemistry data, calculating cross sections and rate coefficients, and quantifying sulfur atom yields in different states relevant to the diffuse interstellar medium.

Contribution

It introduces the inclusion of $^4\Pi$ states in the modeling of SH+ recombination using quantum defect theory, providing more comprehensive atomic yield predictions.

Findings

Quantified sulfur atom production in ground and excited states.

Calculated dissociative recombination cross sections and rate coefficients.

Extended previous models with new quantum chemistry data.

Abstract

Our previous study on dissociative recombination of ground state SH$^+$ into $^2\Pi$ states of SH is extended by taking into account the contribution of $^4\Pi$ states recently explored by quantum chemistry methods. Multichannel quantum defect theory is employed for the computation of cross sections and rate coefficients for dissociative recombination, but also for vibrational excitation. Furthermore, we produce the atomic yields resulting from recombination, quantifying the generation of sulfur atoms in their ground (\mbox{$^3$P}) and lowest excited (\mbox{$^1$D}) states respectively.