PGI-1 Seminar: Dr. Nektarios Lathiotakis
Local Effective Potentials with Correct Asymptotic Behavior in DFT and Reduced-Density-Matrix-Functional Theory
- 24 Jul 2013 11:30
National Hellenic Research Foundation, Athens, Greece
We propose to minimize orbital functionals in terms of a local effective potential under two subsidiary conditions, in terms of the effective electron density that corresponds to the electron-electron interaction part of the effective potential. The first of these conditions is that the total effective charge is N-1 electrons, a property of the exact Kohn-Sham potential. The second is the positivity of the effective density. These conditions can be easily applied if the total energy functional is minimized in terms of the effective density. By employing the first of these conditions, the asymptotic behavior of the effective potential is correcting, thus self-interactions are largely corrected.
This idea is applied to standard DFT approximations, like LDA, leading to correct ionization potentials. It is also applied to the minimization of reduced density matrix functionals in terms of the natural orbitals. In this way natural orbitals are assumed to correspond to a local potential. Although an approximate minimization we demonstrate that it has certain advantages. Such an advantage is computational efficiency. Most importantly, it leads to the definition of a single electron spectra in reduced density functional theory. We show numerically that one can get single electron properties close to experiment while other quality features of reduced density matrix functionals like the correct dissociation of molecules is not affected by the additional local potential approximation.
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