Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance work on Wednesday 27th March 2019 from 11:00 AM to 1:00 PM (GMT).

During this time our website performance may be temporarily affected. We apologise for any inconvenience this might cause and thank you for your patience.


Issue 1, 2014
Previous Article Next Article

Kinetic isotope effect in malonaldehyde determined from path integral Monte Carlo simulations

Author affiliations

Abstract

The primary H/D kinetic isotope effect on the intramolecular proton transfer in malonaldehyde is determined from quantum instanton path integral Monte Carlo simulations on a fully dimensional and validated potential energy surface for temperatures between 250 and 1500 K. Our calculations, based on thermodynamic integration with respect to the mass of the transferring particle, are significantly accelerated by the direct evaluation of the kinetic isotope effect instead of computing it as a ratio of two rate constants. At room temperature, the KIE from the present simulations is 5.2 ± 0.4. The KIE is found to vary considerably as a function of temperature and the low-T behaviour is dominated by the fact that the free energy derivative in the reactant state increases more rapidly than in the transition state. Detailed analysis of the various contributions to the quantum rate constant together with estimates for rates from conventional transition state theory and from periodic orbit theory suggest that the KIE in malonaldehyde is dominated by zero point energy effects and that tunneling plays a minor role at room temperature.

Graphical abstract: Kinetic isotope effect in malonaldehyde determined from path integral Monte Carlo simulations

Back to tab navigation

Publication details

The article was received on 02 Sep 2013, accepted on 16 Oct 2013 and first published on 29 Oct 2013


Article type: Paper
DOI: 10.1039/C3CP53698J
Citation: Phys. Chem. Chem. Phys., 2014,16, 204-211

  •   Request permissions

    Kinetic isotope effect in malonaldehyde determined from path integral Monte Carlo simulations

    J. Huang, M. Buchowiecki, T. Nagy, J. Vaníček and M. Meuwly, Phys. Chem. Chem. Phys., 2014, 16, 204
    DOI: 10.1039/C3CP53698J

Search articles by author

Spotlight

Advertisements