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# The Role of High Energy Photoelectrons on the Dissociation of Molecular Nitrogen in Earth's Ionosphere

Srimoyee Samaddar, Karthik Venkataramani, Justin Yonker, Scott. M. Bailey

Submitted on 20 September 2022

## Abstract

Soft x-ray radiation from the sun is responsible for the production of high energy photoelectrons in the D and E regions of the ionosphere, where they deposit most of their ionization energy. The photoelectrons created by this process are the main drivers for dissociation of Nitrogen molecule (${N}_{2}$) below 200 km. Furthermore, the dissociation of ${N}_{2}$ is one of main mechanisms of the production of Nitric Oxide (NO) at these altitudes. In order to estimate the dissociation rate of ${N}_{2}$ we need its dissociation cross-sections. The dissociation cross-sections for ${N}_{2}$ by photoelectrons are primarily estimated from the cross-sections of its excitation states using predissociation factors and dissociative ionization channels. Unfortunately, the lack of cross-sections data, particularly at high electron energies and of higher excited states of ${N}_{2}$ and ${N}_{2}^{+}$, introduces a lot of uncertainty in the dissociation rate calculation, which subsequently leads to uncertainties in the NO production rate from this source.

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Subjects: Physics - Chemical Physics; Astrophysics - Earth and Planetary Astrophysics; Physics - Atmospheric and Oceanic Physics