Ab initio calculations of optical absorption spectra: Solution of the Bethe-Salpeter equation within density matrix perturbation theory

ORAL

Abstract

We present an approach to compute optical absorption spectra from first principles, which is suitable for the study of large systems and gives access to spectra within a wide energy range. In this approach, the quantum Liouville equation is solved iteratively within first order perturbation theory, with a Hamiltonian containing a static self-energy operator [1]. This is equivalent to solving the Bethe-Salpeter equation. Explicit calculations of single particle excited states and inversion of dielectric matrices are avoided using techniques based on Density Functional Perturbation Theory [1,2]. The calculation and inclusion of GW quasi-particle corrections within this framework are discussed. The efficiency and accuracy of our approach are demonstrated by computing optical spectra of solids, nanostructures and dipeptide molecules exhibiting charge transfer excitations. \\[4pt] [1] D.Rocca, D.Lu and G.Galli, J. Chem. Phys. 133, 164109 (2010). \\[0pt] [2] H. Wilson, F. Gygi and G. Galli, Phys. Rev. B , 78, 113303, (2008).

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Authors

  • Dario Rocca

    UC Davis, University of California-Davis, Department of Chemistry, University of California, Davis

  • Deyu Lu

    Brookhaven National Laboratory, Center for Functional Nanomaterials, Brookhaven National Laboratory

  • Viet Huy Nguyen

    University of California-Davis, UC Davis, University of California, Davis, USA

  • Giulia Galli

    University of California, Davis, Department of Chemistry and Department of Physics, University of California at Davis, Davis, California, USA, Department of Chemistry \& Department of Physics, Unversity of California, Davis, Department of Chemistry and Department of Physics, UC Davis, UC Davis, University of California-Davis, Department of Chemistry and Department of Physics, University of California, Davis, Univeristy of California, Davis, University of California Davis, Davis, CA95616, University of California, Davis, USA