Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 16: Electronic Structure and Spectroscopy II
CPP 16.2: Vortrag
Mittwoch, 29. März 2006, 14:15–14:30, ZEU 160
Double-Pole Approximation in Time-Dependent Density Functional Theory — •H. Appel1, E.K.U. Gross1, and K. Burke2 — 1Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin-Dahlem, Germany. — 2Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Rd, Piscataway, NJ 08854.
A simple approximate solution of the TDDFT response equations is the single pole approximation (SPA). By relating the poles of the Kohn-Sham (KS) response function to the poles of the true interacting response function, SPA provides additive shifts that correct the KS excitation energies towards the true excitations of the system. In the present work [1] we have extended the SPA to the case of two strongly coupled poles. The analysis provides a variety of new results beyond those of SPA. Most importantly, one can determine the regimes where SPA fails and provide corrections in that case. In addition corrections to oscillator strengths become accessible by using the double-pole approximation (DPA). Within the DPA we show that in certain regimes the coupling between poles can cause a transition to vanish entirely from the optical spectrum. DPA has recently been successfully applied to core-hole interaction in the X-ray absorption spectroscopy of 3d transition metals [2].
[1] Double-Pole Approximation in Time-Dependent Density Functional Theory, H. Appel, E.K.U. Gross, K. Burke, cond-mat/0510396
[2] Measuring the kernel of time-dependent density functional theory with X-ray absorption spectroscopy of 3d transition metals, A. Scherz, E.K.U. Gross, H. Appel, C. Sorg, K. Baberschke, H. Wende, and K. Burke, Phys. Rev. Lett., in print.