Infrared spectroscopy of organic molecules trapped in solid parahydrogen: Applications in Hydrogen of clustering and in situ UV photolysis

One unique aspect to the synthesis of chemically-doped parahydrogen (pH 2) solids is that there is always some amount (<300 ppm) of residual orthohydrogen (oH2) present. One consequence of this that my research has investigated is that oH2 molecules preferentially cluster to the organic dopant leading to resolvable perturbations to the high-resolution infrared spectrum of the chemical dopant. The FTIR spectra of formic acid and N-methylacetamide solvated in solid molecular hydrogen (SMH) crystals with varying amounts of oH2 are presented in order to elucidate the effects of oH2 clustering on the high-resolution vibrational spectra of these molecules.;The in situ photochemistry of molecular precursors in SMH is expected to be very different from the analogous photochemistry in the gas phase and rare gas matrices. The results of the 193 nm photolysis of formic acid in solid pH2 are presented and confirm basic differences in the branching ratios between products from analogous studies in rare gas matrices. These studies help quantify the lack of a cage effect in solid pH2 for the UV photolysis of precursors. Further, this qualitative difference in the in situ UV photochemistry permits high concentrations of radicals to be photogenerated allowing low temperature radical chemistry to be explored.