LOCAL-SCALING TRANSFORMATION FUNCTION AND ATOMIC SHELL STRUCTURE IN DENSITY-FUNCTIONAL THEORY

The method of local scaling transformation in density functional theory calculates a transformation function (TRF) in order to generate an optimized atomic N-electron wave function from a trial density and a reference density/wave function. The TRFs f(r) for several atomic systems are studied and it is observed that the number of minima in df(r)/dr equals the number of atomic shells, except when rho = rho0 and f = r.