Recent new developments of steady-state and time-dependent density functional theories for the treatment of structure and dynamics of many-electron atomic, molecular, and quantum dot systems

We present a short account of recent new developments of density-functional theory (DFT) for accurate and efficient treatments of the electronic struc ture and quantum dynamics of many-electron systems. The conventional DFT ca lculations contain spurious self-interaction energy and improper long-range potential, preventing reliable description of the excited and resonance st ates. We present a new DFT with optimized effective potential (OEP) and sel f-interaction-correction (SIC) to overcome some of the major difficulties e ncountered in conventional DFT treatments using explicit energy functionals . The OEP-SIC formalism uses only orbital-independent single-particle local potentials and is self-interaction free, providing a theoretical framework for accurate description of the excited-state properties and quantum dynam ics. Several applications of the new procedure are presented, including: (a ) the first successful DFT treatment of the atomic autoionizing resonances, (b) a relativistic extension of the OEP-SIC formalism for the calculation of the atomic structure with results in good agreement with the experimenta l data across the periodic table (Z = 2-106), (c) electronic structure calc ulation of the ionization properties of molecules, and (d) the delicated "s hell-filling" electronic structure in quantum dots. Finally we present also new formulations of time-dependent DFT for nonperturbative treatment of at omic and molecular multiphoton and nonlinear optical processes in intense a nd superintense laser fields. Both the time-independent Floquet approach an d the time-dependent OEP-SIC technique are introduced. Application of the t ime-dependent DFT/OEP-SIC procedure to the study of multiple high-order har monic generation processes in intense ultrashort pulsed laser fields is dis cussed in detail.