Theoretical approaches and mechanistic applications in the gas to condensed phase transition of high energy heavy halogen reactions in organic systems

The kinetic energy spectra of 80Br/sup m/(I.T.)80Br and 130I/sup m/(I.T.)130I were calculated for comparison with kinetic theory energy requirements. For the bromine activation in Br2, the kinetic energy ranged from 0 to 153 eV and for the analogous iodine system the range was from 0 to 78 eV, and therefore a major portion of (I.T.)-activated bromine and iodine ions fail to meet kinetic theory requirements. Bromine reactions activated by (n,γ)- and (I.T.)-processes were studied in halomethanes. Gas phase systematic trends were shown to be due to differences in activation and a definitive difference due to activation that is independent of system and suggests the importance of enhancement at higher densities is shown by the variation of total and individual organic product yields with density. The gas to condensed phase transition technique was also used to study the 130I--ethane system. Total organic product yields were found to vary over a 60-fold range. Evaluation of the data suggests the enhancement of direct substitution reactions and the presence of a ''caged-complex.'' A computer simulation study was made to test kinetic theory parameters in the gas to condensed phase transition. The study was modeled after the iodine-128--acetylene system which proceeds via one reaction intermediate. The model exhibited good agreement with kinetic theory in sensitivity to reaction cross section and insensitivity to mass and initial energy. Disagreement was found in sensitivity to nonreactive collisional energy loss. Further disagreement was found in the reaction probability functions which suggest that kinetic theory cannot be applied without modification by chemical parameters