THE ROHF EXTENSION OF THE STATISTICAL POPULATION ANALYSIS OF ELECTRON AND SPIN-DENSITIES

In this work we use once again the first-order reduced density operator formalism to derive the statistical population analysis for ROHF wavefunctions, along the same lines as we have done before for other types of wavefunctions. In this way we find a partition of the electron density and a partition of the uncoupled spin density. The formalism is completely general and an be applied to any molecular wavefunction, whether ab initio in any level of accuracy, or semi-empirical. Numerical examples are given for systems described by an ROHF wavefunction obtained at the semi-empirical AM1 level. The comparison with UHF results is also reported.