Back to Search Start Over

Spurious fractional charge on dissociated atoms: Pervasive and resilient self-interaction error of common density functionals.

Spurious fractional charge on dissociated atoms: Pervasive and resilient self-interaction error of common density functionals.

Authors :
Ruzsinszky, Adrienn
Perdew, John P.
Csonka, Gábor I.
Vydrov, Oleg A.
Scuseria, Gustavo E.
Source :
Journal of Chemical Physics. 11/21/2006, Vol. 125 Issue 19, p194112. 8p. 3 Charts, 5 Graphs.
Publication Year :
2006

Abstract

Semilocal density functional approximations for the exchange-correlation energy can improperly dissociate a neutral molecule XY (Y≠X) to fractionally charged fragments X+q...Y-q with an energy significantly lower than X0...Y0. For example, NaCl can dissociate to Na+0.4...Cl-0.4. Generally, q is positive when the lowest-unoccupied orbital energy of atom Y0 lies below the highest-occupied orbital energy of atom X0. The first 24 open sp-shell atoms of the Periodic Table can form 276 distinct unlike pairs XY, and in the local spin density approximation 174 of these display fractional-charge dissociation. Finding these lowest-energy solutions with standard quantum chemistry codes, however, requires special care. Self-interaction-corrected (SIC) semilocal approximations are exact for one-electron systems and also reduce the spurious fractional charge q. The original SIC of Perdew and Zunger typically reduces q to 0. A scaled-down SIC with better equilibrium properties sometimes fails to reduce q all the way to 0. The desideratum of “many-electron self-interaction freedom” is introduced as a generalization of the one-electron concept. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
125
Issue :
19
Database :
Academic Search Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
23250139
Full Text :
https://doi.org/10.1063/1.2387954