DETERMINATION OF NET ATOMIC CHARGES USING A MODIFIED PARTIAL EQUALIZATION OF ORBITAL ELECTRONEGATIVITY METHOD .4. APPLICATION TO HYPERVALENT SULFUR-CONTAINING AND PHOSPHORUS-CONTAINING MOLECULES

The parameters for an empirical point charge calculation method, Mulli ken Population Constrained Potential Derived-Modified Partial Equaliza tion of Orbital Electronegativity (MPCPD-MPEOE) method, for hypervalen t sulfur, phosphorus, and the atoms bonded to these atoms, were determ ined. A new empirical method, MPCPD, which has inherent advantages ove r both the Mulliken population and potential derived methods, is propo sed here. The MPCPD net atomic charges are transferable and reproduce the electrostatic potential. The electrical properties were calculated with the MPCPD and MPCPD-MPEOE charges. These properties agreed well with experimental results and with 6-31G* ab initio results. The MPEO E parameters for the sulfur atom in aromatic molecules and trivalent p hosphorus in phosphite molecules were also determined. The dipole mome nts calculated with the MPCPD-MPEOE point charges agreed well with exp erimental results. All the parameters obtained in this work are consis tent with those obtained in our previous work. (C) 1995 by John Wiley & Sons, Inc.