First-Principles Optical Response of Extended Systems from Time- Dependent Density-Functional Theory March 20, 2012

Venue/Location: Room G50, Newton Building, University of Salford
Event type:
Description: Leonardo Bernasconi, D.Phil. (Oxon), STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire, UK

Abstract:

The development of accurate electronic structure methods to account for the response of a quantum system of nuclei and electrons to an electromagnetic radiation of optical or UV frequency is currently a very active and complex area of research in solid state physics and materials science.

Time-dependent density-functional theory (TD-DFT) has emerged in recent years as a powerful and general tool to study from first principles the interaction of radiation with matter and to address the calculation of a number of properties involving electronic excitations in finite and extended systems.

In this talk I will present a new formulation of the TD-DFT equations for the accurate and efficient calculation of the optical response of infinite (periodic) systems.

The method is formulated within the linear-response approximation, but it can easily be extended to include higher-order response contributions, and it is implemented in the all-electron Gaussian basis set code CRYSTAL.

I will outline the formal foundation of the method, describe its analogy with time-dependent coupled-perturbed Hartree-Fock theory, and demonstrate its accuracy in the description of the optical response of crystalline semiconductors and insulators, oxides and disordered materials, including, in particular, excitonic systems.

I will also briefly address the use of TD-DFT in simulating real-time excited state nuclear dynamics. In this context, I will present results on photo-induced dynamics, topological defect formation and charge transport in infinite polyacetylene chains.

For further information, please contact: Dr Pietro Murano, PG Director Tel: 0161 295 3531 or email: [email protected]

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Official Website: http://www.salford.ac.uk/home-page/events/events/first-principles-optical-response-of-extended-systems-from-time-dependent-density-functional-theory