POLARIZATION-CORRECTED ELECTROSTATIC POTENTIALS OF AROMATIC-COMPOUNDS

The electrostatic potentials (EPS) corrected for polarization (TPS) of the aromatic compounds benzene, aniline, chlorobenzene, nitrobenzene, phenol, benzamide, and N-phenylacetamide have been calculated at the ab initio SCF level within three basis sets: 6-31G*, MINI-1, and STO- 3G. For chlorobenzene in its MINI-1-optimized geometry, the calculatio n was also performed within MINI-1*. By reference to 6-31G**, the MIN I-1-computed EP is much more satisfactory than the STO-3G-computed EP, whereas the MINI-I and STO-3G basis sets give very similar total pote ntials corrected for polarization (TPs). The MINI-1* basis set appear s to be miscalibrated for computing EPs. It provides qualitative resul ts that differ from those obtained with the 6-31G* basis set. The EP has a negative well above the middle of the benzene ring, while the TP exhibits a negative crown just above the benzene carbon atoms, where electrophilic attack takes place. The TP calculated for the interactio n of nitrobenzene with a hydride ion instead of a proton allowed analy zation of the effects of polarization on the positive EP above the N-C bond.