Knowledge Bank

High resolution infrared spectroscopy of pure rotational and rovibrational transitions in solid hydrogen has become an area of increasing experimental and theoretical interest in our laboratory. In particular, the tetrahexacontapole induced $AJ=6$ pure rotational transition in solid para hydrogen has been observed to consist of three $components1$ as a result of the interaction of the molecule with the crystal $environment.2$ In order to understand the observed spectrum and to plan future experiments to search for other possible transitions, we use the first principles theory developed by Van $Kranendonk3$ and others to calculate the expected splitting of an arbitrary rotational level and the intensities of the corresponding transitions. We extend the previous calculation by including higher multipole moments and higher order effects. Such a calculation is relevant in view of the high resolution and high sensitivity attainable by laser spectroscopy.