THE INFRARED ABSORPTION SPECTRUM OF $H_{2}$ MOLECULES IN CRYSTALLINE ARGON
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Date
1966
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Ohio State University
Abstract
The induced infrared fundamental band of hydrogen dissolved in crystalline argon was studied in a low temperature cell with an absorption path length of 20 cm. Liquid argon was saturated with hydrogen under pressure and the solution then cooled very slowly to form a transparent solid. The spectrum consists of three sets of lines falling in the regions corresponding to the Q, S(0) and S(1) transitions of the pressure-induced spectrum of gaseous hydrogen. Each of these sets exhibit the same frequency structure of a central line flanked by two pairs of lines shifted by $\pm 23$ and $\pm 118 cm^{-1}$ from the central component, with the intensities of the high and low frequency members of a pair related by a Boltzmann relation. The central components of each set arise from internal transitions of the $H_{2}$ molecules. The stronger components shifted by $\pm 112 cm^{-1}$ can be calculated from a model in which a single $H_{2}$ molecule on a substitutional lattice site moves in the field of its argon neighbours considered to be stationary. Various reasonable interpretations of the weaker components at $\pm 23 cm^{-1}$ can be offered.
Description
Author Institution: Department of Physics, University of Toronto