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Ab initio based classical electrostatic potentials for the interaction between molecules and surfaces

Journal Article · · Journal of Physical Chemistry
DOI:https://doi.org/10.1021/jp953513e· OSTI ID:249661
;  [1]
  1. Pacific Northwest National Lab., Richland, WA (United States)
Molecular dynamics simulations and free energy calculations based on interactions described by hybrid quantum-classical methods are a logical approach to the study of solvent-molecule and solvent-surface interfaces. These techniques exploit the classical nature of long-range interactions to provide a computationally tractable description of complex interfacial systems. The present work develops and tests the performance of a classical electrostatic potential for describing adsorbate/surface interactions. The electrostatic potential is constructed from a numerical representation of the electric potential, field, and field gradients of the bare surface, as a function of position above the surface, combined with the electric multipolar moments of the adsorbate molecules. The former is obtained from periodic Hartree-Fock calculations on the bare surface; the latter is from molecular Hartree-Fock calculations on the isolated molecules. An empirical, short-range repulsive term is added to the classical `long-range` expression for the interaction. The resulting potential is then tested by comparison to periodic Hartree-Fock calculations on the combined adsorbate-surface system. This allows the accuracy of the approximation to be evaluated independent of the level of theory used to compute the electronic charge densities. Results are presented for H{sub 2}O, HCl, and NH{sub 3} adsorbates on the (001) surface of MgO. 26 refs., 11 figs., 2 tabs.
DOE Contract Number:
AC06-76RL01830; FG06-89ER75522
OSTI ID:
249661
Journal Information:
Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 18 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
Country of Publication:
United States
Language:
English