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Optical excitations of Si by time‐dependent density functional theory based on exact‐exchange Kohn–Sham band structure
Author(s) -
Kim YongHoon,
Städele Martin,
Görling Andreas
Publication year - 2002
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10411
Subject(s) - time dependent density functional theory , quasiparticle , density functional theory , physics , condensed matter physics , local density approximation , kohn–sham equations , quantum mechanics , adiabatic process , chemistry , superconductivity
We calculate the imaginary part of the frequency‐dependent dielectric function of bulk silicon by applying time‐dependent density functional theory (TDDFT) based on the exact‐exchange (EXX) Kohn–Sham (KS) band structure and the adiabatic local‐density approximation (ALDA) kernel. The position of the E 2 absorption peak calculated with the EXX band structure at the independent‐particle level is in excellent agreement with experiments, which demonstrate the good quality of EXX “KS quasiparticles.” The excitonic E 1 peak that is missing at the independent‐particle level remains absent if two‐particle interaction effects are taken into account within the ALDA to TDDFT, demonstrating the incapability of the ALDA kernel to describe excitonic effects. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003