INTRINSIC REACTION COORDINATE OF PERTURBED POTENTIAL-ENERGY SURFACES - CONSTRUCTION OF PERTURBED ENERGY PROFILES

This contribution analyzes the changes in the intrinsic reaction coord inate (IRC) and in the potential energy profiles (PEP) caused by appli cation of a uniform electric field evaluated using standard ab initio mo methods. Two typical organic processes have been studied, namely, t he Friedel-Crafts and the Walden inversion reactions, which are modele d by suitable simple systems. The results for the Walden inversion rea ction show that the IRC for the field-free and that for perturbed proc esses are almost coincident; in this case, using the field-free IRC to compute the perturbed energy profile is a very good approximation. On the contrary, for the Friedel-Crafts model reaction, the two IRCs dif fer slightly, so the energy profiles using the perturbed and the unper turbed IRCs are somewhat different. (C) 1993 John Wiley & Sons, Inc.