Modified hybridization displacement charge scheme for pi-electron systems:Study of molecular electrostatic potential maps

A modified form of the hybridization displacement charge scheme (HDC-PI) su itable for application to molecules where pi-electrons play the dominant ro le in controlling molecular electrostatic potential (MEP) features is prese nted. This modified scheme does not only preserve the atomic contributions to molecular dipole moment but also it represents the two opposing componen ts of atomic hybridization dipole moment arising due to pi-electrons, one d ue to the pi-electrons located above the molecular plane and the other due to those located below the plane, so as to reproduce MEP features appropria tely. The method has been applied within the framework of the AM1 and MNDO methods to several different types of molecules containing pi-electrons dem onstrating its very satisfactory performance. (C) 1999 John Wiley & Sons, I nc.