Study on Anharmonic Effect of the Unimolecular Reaction of CH2(D-2)FO

Abstract

Study on the unimolecular reaction for CH2FO and CD2FO is carried out. The structures, energy barriers and zero point energy of the three channels in the title unimolecular reactions are computed with the MP2/6-311++G(3df, 3pd) method. RRKM theory is used to calculate the rate constants of canonical case at temperature range of 500-5000 K and microcanonical system at total energy of 19.05-71.68 kcal/mol. The results indicate that the anharmonic effect and isotope effect are very small for the three channels, and the anharmonic rate constants, around 10(9)-10(11) s(-1), are close to the experimental prediction reasonably.