Physical Review Letters 91, 256402 - 4 (2003)

Bound excitons in time-dependent density-functional-theory: optical and energy-loss spectra

A. Marini, R. Del Sole , A. Rubio

A robust and efficient frequency dependent and nonlocal exchange correlation f_xc(r,r^′;ω) is derived by imposing time-dependent density-functional theory (TDDFT) to reproduce the many-body diagrammatic expansion of the Bethe-Salpeter polarization function. As an illustration, we compute the optical spectra of LiF, SiO₂, and diamond and the finite momentum transfer energy-loss spectrum of LiF. The TDDFT results reproduce extremely well the excitonic effects embodied in the Bethe-Salpeter approach, both for strongly bound and resonant excitons. We provide a working expression for f_xc that is fast to evaluate and easy to implement.

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http://dx.doi.org/10.1103/PhysRevLett.91.256402

Related Research Areas

• Foundations of Time-dependent Density Functional Theory