Abstract
The correct description of multi-reference electronic ground states within Kohn-Sham density functional theory (DFT) requires an ensemble-state representation, employing fractionally occupied orbitals. However, the use of fractional orbital occupation leads to non-normalized exact-exchange holes, resulting in large fractional-spin errors for conventional approximative density functionals. In this communication, we present a simple approach to directly include the exact-exchange-hole normalization into DFT. Compared to conventional functionals, our model strongly improves the description for multi-reference systems, while preserving the accuracy in the single-reference case. We analyze the performance of our proposed method at the example of spin-averaged atoms and spin-restricted bond dissociation energy surfaces. Published by AIP Publishing.
Item Type: | Journal article |
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Research Centers: | Center for Integrated Protein Science Munich (CIPSM) |
Subjects: | 500 Science > 540 Chemistry |
ISSN: | 0021-9606 |
Language: | English |
Item ID: | 68195 |
Date Deposited: | 19. Jul 2019, 12:24 |
Last Modified: | 04. Nov 2020, 13:50 |