H atoms in solid parahydrogen, even at temperatures below 2 K, continue to diffuse through the solid by the H + H2 → H2 + H tunneling exchange reaction. We use in situ photolysis of precursor molecules embedded in a parahydrogen matrix to study H atom reactions with other species in the temperature range between 1.7 and 4.3 K. For the reaction, H + N2O → cis-HNNO we observe an anomalous effect of temperature; the reaction only occurs at temperatures less than 2.4 K. In our preliminary communication of these results [Mutunga, Follett, and Anderson, J. Chem. Phys. 139, 151104 (2013)] we speculated this strange temperature behavior could result from a two-step mechanism that involves formation of a weakly bound encounter complex of the reacting species, H---N2O. In this poster we will present our subsequent work to quantitatively test this hypothesis using a master equation formalism and transition state theories. The models are focused on the gas phase H + N2O reaction at moderately low temperatures (20 to 100 K) with hopes of extending them to even lower temperatures.

Using kinetic models to understand H atom reactions in solid parahydrogen

249th National Meeting (2015)

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Using kinetic models to understand H atom reactions in solid parahydrogen<br />