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Title: Sublinear scaling for time-dependent stochastic density functional theory

A stochastic approach to time-dependent density functional theory is developed for computing the absorption cross section and the random phase approximation (RPA) correlation energy. The core idea of the approach involves time-propagation of a small set of stochastic orbitals which are first projected on the occupied space and then propagated in time according to the time-dependent Kohn-Sham equations. The evolving electron density is exactly represented when the number of random orbitals is infinite, but even a small number (≈16) of such orbitals is enough to obtain meaningful results for absorption spectrum and the RPA correlation energy per electron. We implement the approach for silicon nanocrystals using real-space grids and find that the overall scaling of the algorithm is sublinear with computational time and memory.
Authors:
;  [1] ;  [2] ;  [3]
  1. Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095 (United States)
  2. Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)
  3. Department of Chemistry, University of California and Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Publication Date:
OSTI Identifier:
22415997
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; ABSORPTION SPECTRA; ALGORITHMS; CROSS SECTIONS; DENSITY FUNCTIONAL METHOD; ELECTRON CORRELATION; ELECTRON DENSITY; ELECTRONS; NANOSTRUCTURES; RANDOM PHASE APPROXIMATION; RANDOMNESS; SILICON; STOCHASTIC PROCESSES; TIME DEPENDENCE