Photoionization from the ground and excited vibrational states of H+2 and its deuterated isotopologues

Photoionization cross sections and rate coefficients have been calculated for all bound vibrational levels of the 1s$\sigma_{\mathrm{g}}$ state of H$_{2}^{+}$, HD$^{+}$, and D$_{2}^{+}$. The Born-Oppenheimer approximation is employed in our calculation of vibrationally-resolved photoionization cross sections. Vibrationally-resolved and local thermal equilibrium photoionization rate coefficients are presented for photon temperatures less than $50\,000$ K and are found to be several orders of magnitude larger than previous results in the literature. Analytic fits for the vibrationally-resolved and local thermal equilibrium photoionization rate coefficients are provided. Near threshold oscillations in the vibrationall-resolved photoionization are observed. A benchmark set of photoionization cross sections are presented. Fixed-nuclei photoionization cross sections are calculated using two-center true continuum wave functions and are verified by comparison with previous calculations and are found to be in excellent agreement in all cases. Data files for our set of benchmark cross sections, rate coefficients, and fitting parameters for H$_{2}^{+}$, HD$^{+}$, and D$_{2}^{+}$ are available on Zenodo under an open-source Creative Commons Attribution license: https://doi.org/10.5281/zenodo.8304060 .Comment: Accepted in ApJ

Rayleigh and Raman scattering from alkali atoms

Two computational methods developed recently [McNamara, Fursa, and Bray, Phys. Rev. A 98, 043435 (2018)] for calculating Rayleigh and Raman scattering cross sections for atomic hydrogen have been extended to quasi one-electron systems. A comprehensive set of cross sections have been obtained for the alkali atoms: lithium, sodium, potassium, rubidium, and cesium. These cross sections are accurate for incident photon energies above and below the ionization threshold, but they are limited to energies below the excitation threshold of core electrons. The effect of spin-orbit interaction, importance of accounting for core polarization, and convergence of the cross sections have been investigated. © 2020 by the authors

Cross sections and rate coefficients for photoionization from the ground and excited states of H2+ and its deuterated isotopologues

<p>Photoionization cross sections for all bound vibrational levels of the ground electronic state of H2+, HD+, and D2+. Vibrationally-resolved and local thermal equilibrium rate coefficients have been calculated for radiation temperatures less than 50 000 K. Fitting parameters for an analytic model of the photoionization rate coefficients have been provided. Thermally-averaged photoionization cross sections for gas temperatures of 3 000, 5 000, 8 000, 12 000, 17 000, and 23 000 K have also been included.</p&gt

Photoionization from the Ground and Excited Vibrational States of and Its Deuterated Isotopologues

Photoionization cross sections and rate coefficients have been calculated for all bound vibrational levels of the 1s σ _g state of ${{\rm{H}}}_{2}^{+}$ , HD ^+ , and ${{\rm{D}}}_{2}^{+}$ . The Born–Oppenheimer approximation is employed in our calculation of vibrationally resolved photoionization cross sections. Vibrationally resolved and local thermal equilibrium photoionization rate coefficients are presented for photon temperatures less than 50,000 K and are found to be several orders of magnitude larger than previous results in the literature. Analytic fits for the vibrationally resolved and local thermal equilibrium photoionization rate coefficients are provided. Near-threshold oscillations in the vibrationally resolved photoionization are observed. A benchmark set of photoionization cross sections are presented. Fixed-nuclei photoionization cross sections are calculated using two-center true continuum wave functions and are verified by comparison with previous calculations and are found to be in excellent agreement in all cases. Data files for our set of benchmark cross sections, rate coefficients, and fitting parameters for ${{\rm{H}}}_{2}^{+}$ , HD ^+ , and ${{\rm{D}}}_{2}^{+}$ are available on Zenodo under an open-source Creative Commons Attribution license at doi: https://doi.org/10.5281/zenodo.8304061