The High-resolution Extreme-ultraviolet Spectrum Of N2 By Electron Impact
- The High-resolution Extreme-ultraviolet Spectrum Of N2 By Electron Impact
- Heays, Alan
- Gibson, Stephen
- Lewis, Brenton R.
- Aguilar, Alejandro
- Ajello, Joe M.
- Issue Date
- Planetary atmospheres
- We have recorded high-resolution (FWHM = 0.2\,\AA) extreme-ultraviolet (EUV, 800--1350\,\AA) laboratory emission spectra of molecular nitrogen excited by 20 and 100\,eV electron impact under mostly optically thin conditions. From these, emission cross sections were determined for a total of 491 features arising from N$_2$ electronic-vibrational transitions and atomic N\,I and N\,II multiplets. Molecular emission was observed from those excited levels which are not completely predissociative and to ground-state vibrational levels as high as $v=17$. The frequently-blended molecular emission bands were disentangled with the aid of a coupled-channels model of excited N$_2$ states that includes the strong coupling between valence and Rydberg electronic states and the effects of predissociation. The observed emission bands probe a large range of vibrational motion so that internuclear-distance-dependent electronic transition moments could be deduced experimental. The coupled-channels model could then be used to predict the emission cross sections of unobserved bands and those that are optically thick in the experimental spectra. The electron-impact-induced fluorescence measurements and model were compared with Cassini UVIS observations of emissions from Titan's upper atmosphere.
- International Symposium on Molecular Spectroscopy
- Type of Resource
- Copyright and License Information
- Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/
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