The failure of generalized gradient approximations (GGAs) and meta-GGAs for the two-center three-electron bonds in He-2(+), (H2O)(2)(+), and (NH3)(2)(+)
| Autor: | Myrta Grüning, S. J. A. van Gisbergen, Evert Jan Baerends, Oleg V. Gritsenko |
|---|---|
| Přispěvatelé: | Theoretical Chemistry |
| Jazyk: | angličtina |
| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | Gruning, M, Gritsenko, O V, van Gisbergen, S J A & Baerends, E J 2001, ' The failure of generalized gradient approximations (GGAs) and meta-GGAs for the two-center three-electron bonds in He-2(+), (H2O)(2)(+), and (NH3)(2)(+) ', Journal of Physical Chemistry A, vol. 105, no. 40, pp. 9211-9218 . https://doi.org/10.1021/jp011239k Journal of Physical Chemistry A, 105(40), 9211-9218. American Chemical Society |
| ISSN: | 1089-5639 |
| DOI: | 10.1021/jp011239k |
| Popis: | The radical cations He2+, (H2O)2+, and (NH3)2+ with two-center three-electron A−A bonds are investigated at the configuration interaction (CI), accurate Kohn−Sham (KS), generalized gradient approximation (GGA), and meta-GGA levels. Assessment of seven different GGA and six meta-GGA methods shows that the A2+ systems remain a difficult case for density functional theory (DFT). All methods tested consistently overestimate the stability of A2+: the corresponding De errors decrease for more diffuse valence densities in the series He2+ > (H2O)2+ > (NH3)2+. Upon comparison to the energy terms of the accurate Kohn−Sham solutions, the approximate exchange functionals are found to be responsible for the errors of GGA-type methods, which characteristically overestimate the exchange in A2+. These so-called exchange functionals implicitly use localized holes. Such localized holes do occur if there is left−right correlation, i.e., the exchange functionals then also describe nondynamical correlation. However, in the h... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|