Chemistry of Nuclear Recoil 18F Atoms. VI. Approximate Energetics and Molecular Dynamics in CH3CF3

Abstract

Energetics and molecular dynamics results are reported from an extensive set of high energy recoil ¹⁸F experiments with CH₃CF₃. Based upon thermochemical evidence alone, substantial fractions of the primary hot F‐for‐H, F‐for‐CH₃, and F‐for‐CF₃ reaction products are indicated to involve minimum excitation energies of $\text{7.9 ± 0.2,\hspace{0.17em}9.3 ± 0.1}$ , and $\text{3.5 ± 0.2\hspace{0.17em}}\mathrm{eV}$ , respectively. The primary F‐for‐F reaction products in CH₃CF₃ do not exhibit unimolecular decomposition via a carbon—carbon bond scission mode in apparent violation of RRKM theoretical predictions. The primary F‐for‐H products decompose both via β elimination of HF and via carbon—carbon bond scission in apparent accord with theory. More than one kind of microscopic dynamics is involved in the primary hot F‐for‐H and F‐for‐CH₃ processes in CH₃CF₃ and in the primary hot F‐for‐F process in CF₄. Direct, concerted, and collusive dynamics are required for the higher energy reaction modes for these processes.