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RECORD NUMBER: 13 OF 30

OLS Field Name OLS Field Data
Main Title Multipole Expansion Techniques for the Calculation and Characterization of Molecular Electrostatic Potentials.
Author Rabinowitz, J. R. ; Little, S. B. ;
CORP Author Health Effects Research Lab., Research Triangle Park, NC. ;Environmental Health Research and Testing, Inc., Research Triangle Park, NC.
Year Published 1986
Report Number EPA/600/J-86/315;
Stock Number PB87-176442
Additional Subjects Expansion ; Electrostatics ; Interactions ; Molecules ; Centers ; Normal density functions ; Biology ; Bioassay ; Reprints ; Multipolarity ; Charge distribution ; Gaussian processes
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB87-176442 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/21/1988
Collation 12p
Abstract
The electrostatic interaction between a chemical and its site of biological action is often important in determining biological activity. In order to include this interaction in methods to assess the potential biological activity of large molecules, rapid and reliable techniques are needed for its calculation and characterization. A finite multicenter multipole expansion technique provides a good approximation of the molecular electrostatic potential in circumstances of interest. This technique introduces multipoles at expansion centers within the molecule in addition to atoms. It is difficult to interpret the significance of these multipole terms that are not centered on atoms. Methods are introduced to eliminate the expansion centers and truncate the now infinite multipole expansion. We have found that eliminating all centers with a charge less than .1 of an electron unit has little effect on the results. Two methods for obtaining multipole expansions only at atomic centers are investigated. The expansion of two center charge distributions about the nearest atom is found to give better results than dividing the two center gaussian charge distributions between the atomic centers for the gaussians. (Copyright (c) 1986 by John Wiley and Sons, Inc.)