A DFT-based potential energy surface for the Hmath image cluster

Authors

  • Patricia Barragán,

    1. Instituto de Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
    Current affiliation:
    1. CELIA, Université de Bordeaux-I, UMR CNRS 5107, CEA, 351 Cours de la Libération, F-33045 Talence, France
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  • Rita Prosmiti

    Corresponding author
    1. Instituto de Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
    • Instituto de Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
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Abstract

A global potential energy surface (PES) for the Hmath image complex is presented based on density functional theory (DFT) calculations. We used the B3(H) hybrid functional, a specifically parameterized B3LYP functional for hydrogen-only systems, and we first characterize the equilibrium Hmath image structure. In turn, by comparing with coupled clusterwith single, double and perturbative triples excitations (CCSD(T)) results, we show that the B3(H) predictions are in overall satisfactory and quantitative good agreement with these higher accurate ab initio data for all aspects of the potential, including the correct estimates asymptotic behavior at long Hmath image + H2 distances. Moreover, using the present surface we compute dissociation energies and dissociation enthalpies for the equilibrium Hmath image ⇋ Hmath image + H2 reaction, and compare them with the data available from experimental measurements. In general, a very good accord is found, with the theoretical values from both DFT/B3(H) and CCSD(T) computations to predict somehow a less bound Hmath image cluster than the experimental estimates. Such realistic representations of the potential surfaces of polyatomic systems are of particular interest for studying spectroscopy, collision, and/or fragmentation dynamics, and this is the first attempt for a reasonable description of the Hmath image PES suitable for future direct dynamics simulations. © 2012 Wiley Periodicals, Inc.

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