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Lecture Meta van Faassen


17 March 2005 FWN-Building 5118.-149, Nijenborgh 4, 9747 AG, Groningen
Speaker: Drs. Meta van Faassen
Affiliation: Theoretical Chemistry, RuG
Title: Excitation and response properties of polymers using time-dependent current-density-functional theory
Date: Thu Mar 17, 2005
Start: 16.15
Location: FWN-Building 5118.-149
Host: R. Broer
Telephone: +31 50 363 4374


Time-dependent density-functional theory has the potential to be a very versatile method to calculate various excitation and response properties of large molecular systems. However, the static axial polarizability of conjugated oligomers obtained within this method is greatly overestimated when using the standard adiabatic local density approximation (ALDA). This local approximation, but also the more advanced generalized gradient approximation, is unable to describe the highly nonlocal exchange and correlation effects found in these quasi-one-dimensional systems. We have found a successful approach towards the solution of this longstanding problem by using time-dependent current-density-functional theory, in which we describe these ultranonlocal exchange-correlation effects within a local current description. For the prototype polyacetylene and many other systems excellent agreement with high-level ab initio quantum chemical methods was obtained using the Vignale-Kohn (VK) current-functional. For the long molecular chains and also for a set of benchmark molecules we have obtained the excitation energies and oscillator strengths and we can explain the large reduction of the static polarizability by the way in which the VK-functional modifies these excitation properties. In order to learn more about the VK-functional we did calculations on atoms and we looked at how the polarizability and excitation energies change when the VK-functional is slightly modified.
Last modified:22 October 2012 2.30 p.m.