Numerical stabilities in fitting atomic charges to electric field and electrostatic potential

Ye Mei, John Zhang

Research output: Contribution to journalArticle

Abstract

It is known that electrostatic potential (ESP) derived atomic charges for molecular systems suffer from rank deficiency in least-square fitting. In this paper, we studied numerical properties of atomic charges by fitting to ESP and electric field (EF) for a series of molecular systems, ranging from small molecules to peptides. Our study shows that although atomic charges of certain atoms in a molecule may differ a lot resulting from different fitting schemes, the effect on some observed physical properties of the molecules, such as solvation free energy and radial distributions of the solvent, are negligible. For all the molecules studied in this paper, it is shown that by incorporating EF terms in the least-square fitting, the rank of the least-squares matrix is increased, and the full rank is achieved when only EF terms are included. The current study demonstrates that by using EF, instead of the widely used ESP, in least-square fitting of atomic charges, one can obtain numerically more stable and better defined atomic charges in molecules. Such derived atomic charges may have more desirable properties and better numerical stabilities in studying detailed molecular processes such as in molecular dynamics simulation of macromolecules.

Original languageEnglish (US)
Pages (from-to)925-942
Number of pages18
JournalJournal of Theoretical and Computational Chemistry
Volume8
Issue number5
DOIs
StatePublished - Oct 2009

Fingerprint

numerical stability
Convergence of numerical methods
Electrostatics
Electric fields
electrostatics
Molecules
electric fields
molecules
Solvation
potential fields
Macromolecules
macromolecules
radial distribution
Peptides
Free energy
peptides
solvation
Molecular dynamics
energy distribution
Physical properties

Keywords

  • Charge fit
  • Electric field
  • Electrostatic potential
  • Numerical stability

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Computational Theory and Mathematics
  • Computer Science Applications

Cite this

Numerical stabilities in fitting atomic charges to electric field and electrostatic potential. / Mei, Ye; Zhang, John.

In: Journal of Theoretical and Computational Chemistry, Vol. 8, No. 5, 10.2009, p. 925-942.

Research output: Contribution to journalArticle

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