A statistical study of the methyl nitrite isomerization reaction: inverse secondary isotope effects

Monte Carlo transition-state theory (MCTST) calculations were carried out for the methyl nitrite isomerization reaction. The results obtained in this study were compared with previous classical trajectory calculations in which three different potential energy surfaces were employed. Recrossings of the transition state are a source of disagreement between the trajectory and MCTST rates. However, `direct trajectoriesʹ are the major reason for the deviations. Analysis of the MCTST rates for several deuterium substitutions shows a slight inverse isotope effect, a result in line with the previous trajectory calculations. However, additional MCTST calculations including corrections for zero-point energy effects predict a normal isotope effect.