Density functional resonance theory of unbound electronic systems

Daniel L Whitenack, Purdue University

Abstract

Density Functional Resonance Theory (DFRT) is a complex-scaled version of ground-state Density Functional Theory (DFT) that allows one to calculate in-principle exact resonance energies and lifetimes. The energy and lifetime of the lowest-energy resonance of unbound systems is encoded into a complex "density'' obtained via complex-coordinate scaling. Two electron exactly-solvable models are used to test the theory before proceeding to a three-dimensional implementation which uses approximate functionals. DFRT subsumes ground-state DFT in that it can facilitate calculations for both bound and metastable states, and thus failures of current approximate DFT methods can be studied from a new perspective. Following this line of thinking, derivative discontinuities in the DFT energy functional, orbital energies, and numerical behavior are explored. Finally, a time-dependent version of DFRT is developed to treat high-lying resonances. An analog of the Runge-Gross theorem is established, and the first order complex density response is shown to contain poles at both bound and metastable excitations motivating an eigenvalue problem for calculating excitations.

Degree

Ph.D.

Advisors

Wasserman, Purdue University.

Subject Area

Physical chemistry|Physics|Energy

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