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


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 (N2) below 200 km. Furthermore, the dissociation of N2 is one of main mechanisms of the production of Nitric Oxide (NO) at these altitudes. In order to estimate the dissociation rate of N2 we need its dissociation cross-sections. The dissociation cross-sections for N2 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 N2 and N2+, introduces a lot of uncertainty in the dissociation rate calculation, which subsequently leads to uncertainties in the NO production rate from this source.


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