Reference : Calculation of optical absorption spectra of hydrogenated Si clusters: Bethe-Salpeter eq...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Calculation of optical absorption spectra of hydrogenated Si clusters: Bethe-Salpeter equation versus time-dependent local-density approximation
Benedict, L. X. [> > > >]
Puzder, A. [> > > >]
Williamson, A. J. [> > > >]
Grossman, J. C. [> > > >]
Galli, G. [> > > >]
Klepeis, J. E. [> > > >]
Raty, Jean-Yves mailto [Université de Liège - ULg > Département de physique > Physique de la matière condensée]
Pankratov, O. [> > > >]
Physical Review. B : Condensed Matter
American Institute of Physics
Yes (verified by ORBi)
New York
[en] Theoretical or Mathematical/ Bethe-Salpeter equation ; density functional theory ; dielectric function ; energy gap ; excitons ; hydrogenation ; molecular clusters ; Monte Carlo methods ; nanostructured materials ; silicon compounds ; ultraviolet spectra/ optical absorption spectra ; hydrogenated Si clusters ; Bethe-Salpeter equation ; time-dependent local-density approximation ; model dielectric function ; time-dependent density-functional theory ; adiabatic local-density approximation ; single-particle states ; quasiparticle gap correction ; quantum Monte Carlo calculations ; exchange-correlation kernel ; electron-hole interaction attractive part ; enhanced absorptive features ; strong repulsive Coulomb kernel ; hydrogen-terminated Si nanoclusters ; exciton binding energies ; SiH 4 ; Si 10H 16 ; Si 17H 36 ; Si 29H 24 ; Si 35H 36/ A7840H Visible and ultraviolet spectra of other nonmetals A7125W Electronic structure of solid clusters and nanoparticles A7115M Density functional theory, local density approximation (condensed matter electronic structure) A7820D Optical constants and parameters (condensed matter) A7135 Excitons and related phenomena/ SiH4/bin H4 /bin Si/bin H/bin ; Si10H16/bin Si10/bin H16/bin Si/bin H/bin ; Si17H36/bin Si17/bin H36/bin Si/bin H/bin ; Si29H24/bin Si29/bin H24/bin Si/bin H/bin ; Si35H36/bin Si35/bin H36/bin Si/bin H/bin
[en] We present calculations of the optical absorption spectra of clusters SiH 4, Si 10H 16, Si 17H 36, Si 29H 24, and Si 35H 36, as determined from two different methods: the Bethe-Salpeter equation (BSE) with a model dielectric function, and the time-dependent density-functional theory within the adiabatic local-density approximation (TDLDA). Single-particle states are obtained from local-density approximation (LDA) calculations and, for the BSE calculation, a quasiparticle gap correction is provided by quantum Monte Carlo calculations. We find that the exchange-correlation kernel of the TDLDA has almost no effect on the calculated spectra, while the corresponding attractive part of the electron-hole interaction of the BSE produces enhanced absorptive features at low energies. For the smallest cluster SiH 4, the two methods produce markedly different results, with the TDLDA spectra appearing closer to the experimental result. The gross features of the TDLDA and BSE spectra for larger clusters are however similar, due to the strong repulsive Coulomb kernel present in both treatments
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