| Autor: |
Nafziger, Jonathan, Wasserman, Adam |
| Rok vydání: |
2013 |
| Předmět: |
|
| Zdroj: |
The Journal of Chemical Physics, 143, 234105 (2015) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1063/1.4937771 |
| Popis: |
One of the most important open challenges in modern Kohn-Sham (KS) density-functional theory (DFT) is the correct treatment of fractional electron charges and spins. Approximate exchange-correlation (XC) functionals struggle to do this in a systematic way, leading to pervasive delocalization and static correlation errors. We demonstrate how these errors, which plague density-functional calculations of bond-stretching processes, can be avoided by employing the alternative framework of partition density-functional theory (PDFT), even with simple local and semi-local functionals for the fragments. Our method is illustrated with explicit calculations on the two paradigm systems exhibiting delocalization and static-correlation, stretched H$_2^+$ and H$_2$. We find in both cases our scheme leads to dissociation-energy errors of less than 3%. The effective KS potential corresponding to our self-consistent solutions display key features around the bond midpoint; these are known to be present in the exact KS potential, but are absent from most approximate KS potentials and are essential for the correct description of electron dynamics. |
| Databáze: |
arXiv |
| Externí odkaz: |
|
