Orientational effects in the direct Cl-+CH3Cl SN2 reaction at elevated collision energies:: hard-ovoid line-of-centers collision model

The hard-sphere line-of-centers collision model can be extended analytically to include the orientational dependence of both the energy barrier and the critical distance of approach. This hard-ovoid line-of-centers model is applied to the translational activation of the bimolecular nucleophilic substitution (S(N)2) reaction, Cl- + CH3Cl --> ClCH3 + Cl-, for which a direct reaction mechanism was found in recent classical trajectory calculations. The model is compared with recent experiments and the classical trajectory calculations. (C) 1999 Elsevier Science B.V.