skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization

Abstract

Semi-empirical quantum mechanical methods traditionally expand the electron density in a minimal, valence-only electron basis set. The minimal-basis approximation causes molecular polarization to be underestimated, and hence intermolecular interaction energies are also underestimated, especially for intermolecular interactions involving charged species. In this work, the third-order self-consistent charge density functional tight-binding method (DFTB3) is augmented with an auxiliary response density using the chemical-potential equalization (CPE) method and an empirical dispersion correction (D3). The parameters in the CPE and D3 models are fitted to high-level CCSD(T) reference interaction energies for a broad range of chemical species, as well as dipole moments calculated at the DFT level; the impact of including polarizabilities of molecules in the parameterization is also considered. Parameters for the elements H, C, N, O, and S are presented. The Root Mean Square Deviation (RMSD) interaction energy is improved from 6.07 kcal/mol to 1.49 kcal/mol for interactions with one charged species, whereas the RMSD is improved from 5.60 kcal/mol to 1.73 for a set of 9 salt bridges, compared to uncorrected DFTB3. For large water clusters and complexes that are dominated by dispersion interactions, the already satisfactory performance of the DFTB3-D3 model is retained; polarizabilities of neutral molecules are alsomore » notably improved. Overall, the CPE extension of DFTB3-D3 provides a more balanced description of different types of non-covalent interactions than Neglect of Diatomic Differential Overlap type of semi-empirical methods (e.g., PM6-D3H4) and PBE-D3 with modest basis sets.« less

Authors:
 [1];  [2]
  1. Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706 (United States)
  2. Theoretische Chemische Biologie, Universität Karlsruhe, Kaiserstr. 12, 76131 Karlsruhe (Germany)
Publication Date:
OSTI Identifier:
22493570
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 143; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHARGE DENSITY; COMPARATIVE EVALUATIONS; CORRECTIONS; COVALENCE; DIPOLE MOMENTS; ELECTRON DENSITY; ELECTRONS; MOLECULES; POLARIZABILITY; POLARIZATION; POTENTIALS; QUANTUM MECHANICS; SALTS; VALENCE; WATER

Citation Formats

Christensen, Anders S., E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu, Cui, Qiang, and Elstner, Marcus. Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization. United States: N. p., 2015. Web. doi:10.1063/1.4929335.
Christensen, Anders S., E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu, Cui, Qiang, & Elstner, Marcus. Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization. United States. https://doi.org/10.1063/1.4929335
Christensen, Anders S., E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu, Cui, Qiang, and Elstner, Marcus. 2015. "Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization". United States. https://doi.org/10.1063/1.4929335.
@article{osti_22493570,
title = {Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization},
author = {Christensen, Anders S., E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu and Cui, Qiang and Elstner, Marcus},
abstractNote = {Semi-empirical quantum mechanical methods traditionally expand the electron density in a minimal, valence-only electron basis set. The minimal-basis approximation causes molecular polarization to be underestimated, and hence intermolecular interaction energies are also underestimated, especially for intermolecular interactions involving charged species. In this work, the third-order self-consistent charge density functional tight-binding method (DFTB3) is augmented with an auxiliary response density using the chemical-potential equalization (CPE) method and an empirical dispersion correction (D3). The parameters in the CPE and D3 models are fitted to high-level CCSD(T) reference interaction energies for a broad range of chemical species, as well as dipole moments calculated at the DFT level; the impact of including polarizabilities of molecules in the parameterization is also considered. Parameters for the elements H, C, N, O, and S are presented. The Root Mean Square Deviation (RMSD) interaction energy is improved from 6.07 kcal/mol to 1.49 kcal/mol for interactions with one charged species, whereas the RMSD is improved from 5.60 kcal/mol to 1.73 for a set of 9 salt bridges, compared to uncorrected DFTB3. For large water clusters and complexes that are dominated by dispersion interactions, the already satisfactory performance of the DFTB3-D3 model is retained; polarizabilities of neutral molecules are also notably improved. Overall, the CPE extension of DFTB3-D3 provides a more balanced description of different types of non-covalent interactions than Neglect of Diatomic Differential Overlap type of semi-empirical methods (e.g., PM6-D3H4) and PBE-D3 with modest basis sets.},
doi = {10.1063/1.4929335},
url = {https://www.osti.gov/biblio/22493570}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 8,
volume = 143,
place = {United States},
year = {Fri Aug 28 00:00:00 EDT 2015},
month = {Fri Aug 28 00:00:00 EDT 2015}
}