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

Monte Carlo transition-state theory (MCTST) calculations were carried out f or the methyl nitrite isomerization reaction. The results obtained in this study were compared with previous classical trajectory calculations in whic h three different potential energy surfaces were employed. Recrossings of t he transition state are a source of disagreement between the trajectory and MCTST rates. However, 'direct trajectories' are the major reason for the d eviations. Analysis of the MCTST rates for several deuterium substitutions shows a slight inverse isotope effect, a result in line with the previous t rajectory calculations. However, additional MCTST calculations including co rrections for zero-point energy effects predict a normal isotope effect. (C ) 1999 Elsevier Science B.V. All rights reserved.