Reaction dynamics on barrierless reaction surfaces: A model for isoergic gashyphen;phase protonhyphen;transfer reactions

摘要

The kinetics of some gashyphen;phase alcohol/alkoxide protonhyphen;transfer reactions is slower than predicted by simple Ricendash;Ramsbergerndash;Kasselndash;Marcus (RRKM) rate theory modeling on the nearhyphen;barrierless reaction surfaces. Reaction dynamics can be investigated in isolation from nonequilibrium and/or thermodynamic considerations through the study of a generic isoergic ionndash;molecule system Xminus;+Xminus;H. Monte Carlo quasiclassical trajectory simulations on barrierless reaction surfaces show that the slow experimental kinetics is consistent with both (i) locking of the external rotations of the reactants and (ii) passage over the (orbital angular momentum) centrifugal barrier being the ratehyphen;determining steps in bimolecular association, rather than only the latter process. In addition, there may be nonhyphen;RRKM product selectivity.