Force field modeling of conformational energies: Importance of multipole moments and intramolecular polarization

The ability of force fields to reproduce relative conformational energies for seven molecules is probed. The correlation against LMP2/cc-pVTZ results for standard force field employing fixed partial charges deteriorates as the molecules become more polar. Inclusion of multipole moments and intramolecular polarization can improve the correlation, and both contributions are of similar importance. (C) 2006 Wiley Periodicals, Inc.