PMID- 15740231
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20060517
LR  - 20050302
IS  - 0021-9606 (Print)
IS  - 0021-9606 (Linking)
VI  - 122
IP  - 4
DP  - 2005 Jan 22
TI  - Improving the orbital-free density functional theory description of covalent 
      materials.
PG  - 44103
AB  - The essential challenge in orbital-free density functional theory (OF-DFT) is to 
      construct accurate kinetic energy density functionals (KEDFs) with general 
      applicability (i.e., transferability). During the last decade, several 
      linear-response (LR)-based KEDFs have been proposed. Among them, the 
      Wang-Govind-Carter (WGC) KEDF, containing a density-dependent response kernel, is 
      one of the most accurate that still affords a linear scaling algorithm. For 
      nearly-free-electron-like metals such as Al and its alloys, OF-DFT employing the 
      WGC KEDF produces bulk properties in good agreement with orbital-based Kohn-Sham 
      (KS) DFT predictions. However, when OF-DFT, using the WGC KEDF combined with a 
      recently proposed bulk-derived local pseudopotential (BLPS), was applied to 
      semiconducting and metallic phases of Si, problems arose with convergence of the 
      self-consistent density and energy, leading to poor results. Here we provide 
      evidence that the convergence problem is very likely caused by the use of a 
      truncated Taylor series expansion of the WGC response kernel. Moreover, we show 
      that a defect in the ansatz for the first-order reduced density matrix underlying 
      the LR KEDFs limits the accuracy of these KEDFs. By optimizing the two free 
      parameters involved in the WGC KEDF, the two-body Fermi wave vector mixing 
      parameter gamma and the reference density rho* used in the Taylor expansion, 
      OF-DFT calculations with the BLPS can achieve semiquantitative results for nine 
      phases of bulk silicon. These new parameters are recommended whenever the WGC 
      KEDF is used to study nonmetallic systems.
CI  - (c) 2005 American Institute of Physics.
FAU - Zhou, Baojing
AU  - Zhou B
AD  - Department of Chemistry and Biochemistry, University of California-Los Angeles, 
      Los Angeles, CA 90095-1569, USA.
FAU - Ligneres, Vincent L
AU  - Ligneres VL
FAU - Carter, Emily A
AU  - Carter EA
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
EDAT- 2005/03/03 09:00
MHDA- 2005/03/03 09:01
CRDT- 2005/03/03 09:00
PHST- 2005/03/03 09:00 [pubmed]
PHST- 2005/03/03 09:01 [medline]
PHST- 2005/03/03 09:00 [entrez]
AID - 10.1063/1.1834563 [doi]
PST - ppublish
SO  - J Chem Phys. 2005 Jan 22;122(4):44103. doi: 10.1063/1.1834563.