PNNL

Abstract

We study the prototypical SN2 reaction Cl– + CH3Cl -> CH3Cl + Cl– in water using QM/MM computer simulations with transition path sampling and inertial likelihood maximization. We have identified a new solvent coordinate that improves upon the original atom-exchange coordinate used in the classic analysis by Chandrasekhar, Smith, and Jorgensen.1 The new solvent coordinate quantifies instantaneous solvent induced polarization relative to equilibrium charge density at each point along the reaction pathway. We will present free energy surfaces, transmission coefficients, and committor tests associated with this collective coordinate.