Photodissociation of interstellar N2

TL;DR

This paper provides detailed quantum-mechanical simulations of N2 photodissociation in interstellar environments, offering accurate rates for chemical models and analyzing their impact on various astrophysical settings.

Contribution

It introduces high-resolution line-by-line N2 photodissociation spectra and rates based on recent theoretical and experimental data, improving interstellar chemistry modeling.

Findings

New N2 photodissociation rates for interstellar conditions

Significant impact on chemical models of clouds and disks

Enhanced understanding of nitrogen chemistry in space

Abstract

Molecular nitrogen is one of the key species in the chemistry of interstellar clouds and protoplanetary disks and the partitioning of nitrogen between N and N2 controls the formation of more complex prebiotic nitrogen-containing species. The aim of this work is to gain a better understanding of the interstellar N2 photodissociation processes based on recent detailed theoretical and experimental work and to provide accurate rates for use in chemical models. We simulated the full high-resolution line-by-line absorption + dissociation spectrum of N2 over the relevant 912-1000 \AA\ wavelength range, by using a quantum-mechanical model which solves the coupled-channels Schr\"odinger equation. The simulated N2 spectra were compared with the absorption spectra of H2, H, CO, and dust to compute photodissociation rates in various radiation fields and shielding functions. The effects of the new rates in interstellar cloud models were illustrated for diffuse and translucent clouds, a dense photon dominated region and a protoplanetary disk.