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Author Ivanov, Sergei D. ♦ Grant, Ian M. ♦ Marx, Dominik
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ DIMERS ♦ FORMIC ACID ♦ FREE ENERGY ♦ HYDROGEN ♦ PATH INTEGRALS ♦ POTENTIAL ENERGY ♦ PROTONS ♦ SURFACES
Abstract With the goal of computing quantum free energy landscapes of reactive (bio)chemical systems in multi-dimensional space, we combine the metadynamics technique for sampling potential energy surfaces with the ab initio path integral approach to treating nuclear quantum motion. This unified method is applied to the double proton transfer process in the formic acid dimer (FAD), in order to study the nuclear quantum effects at finite temperatures without imposing a one-dimensional reaction coordinate or reducing the dimensionality. Importantly, the ab initio path integral metadynamics technique allows one to treat the hydrogen bonds and concomitant proton transfers in FAD strictly independently and thus provides direct access to the much discussed issue of whether the double proton transfer proceeds via a stepwise or concerted mechanism. The quantum free energy landscape we compute for this H-bonded molecular complex reveals that the two protons move in a concerted fashion from initial to product state, yet world-line analysis of the quantum correlations demonstrates that the protons are as quantum-uncorrelated at the transition state as they are when close to the equilibrium structure.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-09-28
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 143
Issue Number 12


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