Can quasiclassical trajectory calculations reproduce the extreme kinetic isotope effect observed in the muonic isotopologues of the H + H2 reaction?

Abstract

Rate coefficients for the mass extreme isotopologues of the H + H 2 reaction, namely, Mu H2, where Mu is muonium, and He H2, where He is a He atom in which one of the electrons has been replaced by a negative muon, have been calculated in the 200-1000 K temperature range by means of accurate quantum mechanical (QM) and quasiclassical trajectory (QCT) calculations and compared with the experimental and theoretical results recently reported by Fleming [Science 331, 448 (2011)]10.1126/science.1199421. The QCT calculations can reproduce the experimental and QM rate coefficients and kinetic isotope effect (KIE), kMu(T)kHe(T), if the Gaussian binning procedure (QCT-GB) - weighting the trajectories according to their proximity to the right quantal vibrational action - is applied. The analysis of the results shows that the large zero point energy of the MuH product is the key factor for the large KIE observed. © 2011 American Institute of Physics.