Reactive collision dynamics vibrational energy effects

The RRKM theory is a ubiquitous tool for studying dissociation or isomerization rates of molecules as a function of their vibrational energy. Still highly active in the theoretical field, Marcus has tackled such issues as the semiclassical theory for inelastic and reactive collisions, devising reaction coordinates, new tunneling paths, and exploring solvent dynamics effects on unim-olecular reactions in clusters. 

Several recently published theoretical works predict an interesting effect of vibrational excitation on the reactivity. In a theoretical study Arnold et al. investigated the vibrationally assisted reaction of the Oj-NO vdW complex. They found that the dynamics resembled that of chemical reactions occurring under matrix isolation and differ significantly from the O3 + NO bimo-lecular collision dynamics. Mode sp>ecificity, vibrational predissociation, and intermodal energy transfer were found. The asymmetric stretching mode of O3 is found to be the most effective promoting mode. 

The presence of spin-orbit coupling in the isolated diatomic suggests that nonadiabatic effects could play a major role in the description of the collision dynamics for the O4 system. It is important to emphasize that so far all dynamical calculations have relied on a single potential energy surface bodi for vibrational relaxation and for reactive processes. 

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