Abstract
In the detailed study of unimolecular reactions, a long-standing problem has involved the evaluation of the distribution of energized reactant species. In the conventional pyrolysis experiment, this distribution may be described by the Maxwell-Boltzmann equation. However, in many non-thermal systems of interest, the excitation distribution has no obvious analytical form defining its shape or limits. In this work, a general numerical method was developed which deductively solves for this distribution. Currently a new class on unimolecular reactions resulting from nuclear recoil hot atom substitution has attracted much interest. Due to the experimental convenience and large volume of unresolved data present in the literature, hot atom chemical activation was chosen as the prototype system for this work. In this highly energetic system, the distribution covers a very wide range (10 eV) and has a characteristic shape for which no adequate approximation has yet been made. For any non-thermally activated system there are generally two reaction channels available, collisional stabilization (a pressure dependent event) and decomposition (an energy dependent event). The observed ratio of products from these two reaction channels is intrinsically dependent on the energy distribution of activated species. Therefore, a useful method for indirectly studying the excitation distribution involves the detailed consideration of the effects of energy and pressure on product yields.
Smith, William Stewart (1974). The evaluation of the distribution of excited molecules prior to unimolecular decomposition in non-thermal systems. Doctoral dissertation, Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -173241.