Molecular and Atomic Dipole Moments in Heteronuclear and Homonuclear Diatomics. Density Functional Approach

摘要

In our previous work (Itskowitz, P.; Berkowitz, M. L. J. Phys. Chem. A 1997, 101, 5687), we showed how in the framework of density functional theory the energy of a molecule can be expressed as a functional of the perturbations on atomic densities. In this work we develop an approximation for these perturbations that assigns two charge distributions to each atom. With the help of this approximation, we obtain the values of the net charges for a number of heteronuclear diatomic molecules with the average error of only 5.4% compared to the experimental data. Our approach also allows us to treat homonuclear diatomics in the same way as heteronuclear. In the limit of a point dipole approximation to the charge distribution on an atom in homonuclear diatomics we obtain results which are in a reasonable agreement with the results from ab initio calculations.