Chemical Dynamics Simulations of Gas Phase SN2 Nucleophilic Substitution Reactions

by Prof. William Hase (Texas Tech University)

Monday 31 May 2010, 10:15 → 11:00 Europe/Stockholm

FA32

Classical trajectory chemical dynamics simulations have been used to study the atomic-level chemical dynamics of gas phase SN2 nucleophilic substitution reactions of the type X- + CH3Y → XCH3 + Y- Some of the simulations are based on direct dynamics for which the potential energy surface is represented by an electronic structure theory and the gradient (and for some applications the Hessian) is obtained directly from this theory. This seminar will discuss the methodology of the simulations and some of the simulation results. The latter will include: (1) the role of reactant translational and vibrational energy on the reaction mechanism and reaction probability; (2) the importance of the X----CH3Y and XCH3---Y- pre- and post-reaction ion-dipole complexes on the reaction dynamics; and (3) the extent of statistical dynamics for these chemical reactions. Particular emphasis will be placed on the Cl- + CH3Cl and Cl- + CH3I reactions.