title: Mechanisms of SN2 reactions: insights from a nearside/farside analysis.
abstract: A nearside/farside analysis of differential cross sections has been performed for the complex-forming SN2 reaction Cl(-) + CH3Br → ClCH3 + Br(-). It is shown that for low rotational quantum numbers a direct "nearside" reaction mechanism plays an important role and leads to anisotropic differential cross sections. For high rotational quantum numbers, indirect mechanisms via a long-lived intermediate complex are prevalent (independent of a nearside/farside configuration), leading to isotropic cross sections. Quantum mechanical interference can be significant at specific energies or angles. Averaging over energies and angles reveals that the nearside/farside decomposition in a semiclassical interpretation can reasonably account for the analysis of the reaction mechanism.
authors.affiliation: Institut für Physikalische Chemie, Universität Göttingen, Tammannstr. 6, D-37077 Göttingen, Germany. sschmat@gwdg.de.
authors.forename: Carsten
authors.initials: C
authors.lastname: Hennig
authors.forename: Stefan
authors.initials: S
authors.lastname: Schmatz