Table of Contents
International Journal of Spectroscopy
Volume 2010, Article ID 371201, 11 pages
http://dx.doi.org/10.1155/2010/371201
Research Article

Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin

1Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
2Physics Department, University of Texas, Austin, TX 78712-1081, USA

Received 21 April 2009; Accepted 18 July 2009

Academic Editor: Chantal Stehle

Copyright © 2010 Xiaoping Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Collision-induced absorption by hydrogen and helium in the stellar atmospheres of cool white dwarfs causes the emission spectra to differ significantly from the expected blackbody spectra of the cores. For detailed modeling of radiative processes at temperatures up to 7000 K, the existing H2H2 induced dipole and potential energy surfaces of high quality must be supplemented by calculations with the H2 bonds stretched or compressed far from the equilibrium length. In this work, we describe new dipole and energy surfaces, based on more than 20 000 ab initio calculations for H2H2. Our results agree well with previous ab initio work (where those data exist); the calculated rototranslational absorption spectrum at 297.5 K matches experiment similarly well. We further report the calculated absorption spectra of H2H2 for frequencies from the far infrared to 20 000 cm1, at temperatures of 600 K, 1000 K, and 2000 K, for which there are no experimental data.