Cosmic ray dissociation of molecular hydrogen and dense cloud chemistry

TL;DR

This paper investigates how the mean kinetic energy of secondary electrons from cosmic rays influences molecular hydrogen dissociation and dense cloud chemistry, revealing significant variations in predicted column densities.

Contribution

It introduces a detailed analysis of secondary electron energies affecting molecular hydrogen dissociation, improving the accuracy of dense cloud chemical models.

Findings

Column densities vary by nearly one dex based on secondary electron energy assumptions.

Different cross-section models significantly impact chemical predictions.

The study highlights the importance of accurate secondary electron energy modeling.

Abstract

Dissociation of molecular hydrogen by secondary electrons produced by cosmic ray or X-ray ionization plays a crucial role in the chemistry of the densest part of molecular clouds. Here we study the effect of the mean kinetic energy of secondary electrons on this process. We compare predictions using a range of secondary electron energies and predictions of the cross-sections with the values in the UMIST database. We find that the predicted column densities change by nearly one dex.