QUANTUM-MECHANICAL INTERPRETATION OF TIME-DEPENDENT DENSITY-FUNCTIONAL THEORY

In this paper we derive the differential virial theorem for both time- dependent (TD) Schrodinger theory and Kohn-Sham (KS) density-functiona l theory. As such we obtain an exact integral expression fbr the TD el ectron-interaction potential of KS theory that is independent of the c hoice of action. The expression, valid for general TD phenomena other than the ionization or scattering process, is afforded the physical in terpretation at each instant of time as being the work done to move an electron in a conservative field. The field is a sum of four componen t fields representative of Pauli and Coulomb correlations, correlation -kinetic effects, and as discovered here, correlations due to the diff erence in current densities of the KS and Schrodinger systems. The int erpretation further reduces to that for the corresponding electron-int eraction potential of stationary-state KS theory for time-independent external potentials. (C) 1998 Elsevier Science B.V.