Diagnostics of collisions between electrons and water molecules in near-ultraviolet and visible wavelengths. (arXiv:1909.08878v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bodewits_D/0/1/0/all/0/1">D. Bodewits</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Orszagh_J/0/1/0/all/0/1">J. Országh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Noonan_J/0/1/0/all/0/1">J. Noonan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Durian_M/0/1/0/all/0/1">M. Ďurian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matejcik_S/0/1/0/all/0/1">Š. Matejčík</a>
We studied dissociation reactions of electron impact on water vapor for
several fragment species at optical and near ultraviolet wavelengths (200 – 850
nm). The resulting spectrum is dominated by the Hydrogen Balmer series, by the
OH (A $^2Sigma^+$ – X $^2Pi$) band, and by the emission of ionic H$_2$O$^+$
(A $^2$A$_1$ – X $^2$B$_1$) and OH$^+$ (A $^3Pi$ – X $^3Sigma^-$) band
systems. Emission cross sections and reaction channel thresholds were
determined for energies between 5 – 100 eV. We find that electron impact
dissociation of H$_2$O results in an emission spectrum of the OH (A
$^2Sigma^+$ – X $^2Pi$) band that is distinctly different than the emission
spectra from other excitation mechanisms seen in planetary astronomy. We
attribute the change to a strongly non-thermal population of rotational states
seen in planetary astronomy. This difference can be utilized for remote probing
of the contribution of different physical reactions in astrophysical
environments.
We studied dissociation reactions of electron impact on water vapor for
several fragment species at optical and near ultraviolet wavelengths (200 – 850
nm). The resulting spectrum is dominated by the Hydrogen Balmer series, by the
OH (A $^2Sigma^+$ – X $^2Pi$) band, and by the emission of ionic H$_2$O$^+$
(A $^2$A$_1$ – X $^2$B$_1$) and OH$^+$ (A $^3Pi$ – X $^3Sigma^-$) band
systems. Emission cross sections and reaction channel thresholds were
determined for energies between 5 – 100 eV. We find that electron impact
dissociation of H$_2$O results in an emission spectrum of the OH (A
$^2Sigma^+$ – X $^2Pi$) band that is distinctly different than the emission
spectra from other excitation mechanisms seen in planetary astronomy. We
attribute the change to a strongly non-thermal population of rotational states
seen in planetary astronomy. This difference can be utilized for remote probing
of the contribution of different physical reactions in astrophysical
environments.
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