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Issue 10, 2012
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Correction to DFT interaction energies by an empirical dispersion term valid for a range of intermolecular distances

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Abstract

The computation of intermolecular interaction energies via commonly used density functionals is hindered by their inaccurate inclusion of medium and long range dispersion interactions. Practical computation of inter- and intra-macrobiomolecule interaction energies, in particular, requires a fairly accurate yet not overly expensive methodology. It is also desirable to compute intermolecular energies not only at their equilibrium (lowest energy) configurations but also over a range of biophysically relevant distances. We present a method to compute intermolecular interaction energies by including an empirical correction for dispersion which is valid over a range of intermolecular distances. This is achieved by optimizing parameters that moderate the empirical correction by explicit comparison of density functional (B3LYP) energies with distance-dependent (DD) reference values obtained at the CCSD(T)/CBS limit. The resulting method, hereafter referred to as B3LYP-DD, yields interaction energies with an accuracy generally better than 1 kcal mol−1 for different types of noncovalent complexes, over a range of intermolecular distances and interaction strengths, relative to the expensive CCSD(T)/CBS standard. For a training set of dispersion interacting complexes, B3LYP-DD interaction energies in combination with diffuse functions display absolute errors equal to or smaller than 0.68 kcal mol−1. The empirical correction does not significantly increase the computational cost as compared to standard density functional calculations. Applications relevant to biomolecular energy and structure, such as prediction of DNA base-pair interactions, are also presented.

Graphical abstract: Correction to DFT interaction energies by an empirical dispersion term valid for a range of intermolecular distances

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Publication details

The article was received on 22 Nov 2011, accepted on 11 Jan 2012 and first published on 02 Feb 2012


Article type: Paper
DOI: 10.1039/C2CP23673G
Citation: Phys. Chem. Chem. Phys., 2012,14, 3414-3424
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    Correction to DFT interaction energies by an empirical dispersion term valid for a range of intermolecular distances

    C. Deligkaris and J. H. Rodriguez, Phys. Chem. Chem. Phys., 2012, 14, 3414
    DOI: 10.1039/C2CP23673G

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