RELIABILITY OF THE AM1 WAVE-FUNCTION TO COMPUTE MOLECULAR ELECTROSTATIC POTENTIALS

The reliability of the semiempirical AM1 wavefunction for computing molecular electrostatic potentials (MEP) is examined. The differences between this procedure and the ab initio SCF MEP lie in the freezing of the inner electrons and in the origin of the first-order density matrix. The characteristics of the AM1-derived MEPs are compared with those of MEPs computed from the MNDO and ab initio (STO-3G, 6-31G and 6-31G*) wavefunctions. The statistical analysis of MEP minima points out the goodness of the AM1 wavefunction for reproducing the depth of the ab initio 6-31G* MEP minima originating from well-defined lone pairs. © 1990.