Ab-initio molecular dynamics study of the S 2 reaction Cl + ClCH CN

Ab-initio molecular dynamics has been used to investigate the S_N2 reaction Cl_- + ClCH₂CN using two different exchange-correlation functionals. The results have been compared with available experimental data and with calculations at the MP2/6-311 + G(d,p) level of theory. As a reference, comparison has also been made with calculations for the Cl_- + CH₃Cl reaction, for which accurate experimental data and higher level ab-initio calculations are available. The ∼0 K energy profile has been calculated. It has been found that the minimum energy reaction pathway is characterized by the formation of a strong H-bond. Differences in the electron distribution along the pathway of the two reactions have also been discussed.