Discontinuities of the exchange-correlation kernel and charge-transfer excitations in time-dependent density functional theory
Autor: | Hellgren, M., Gross, E. K. U. |
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Rok vydání: | 2011 |
Předmět: | |
Druh dokumentu: | Working Paper |
DOI: | 10.1103/PhysRevA.85.022514 |
Popis: | We identify the key property that the exchange-correlation (XC) kernel of time-dependent density functional theory must have in order to describe long-range charge-transfer excitations. We show that the discontinuity of the XC potential as a function of particle number induces a space -and frequency-dependent discontinuity of the XC kernel which diverges as $r\to\infty$. In a combined donor-acceptor system, the same discontinuity compensates for the vanishing overlap between the acceptor and donor orbitals, thereby yielding a finite correction to the Kohn-Sham eigenvalue differences. This mechanism is illustrated to first order in the Coulomb interaction. Comment: 6 pages, 3 figures (expanded version, accepted in Phys. Rev. A) |
Databáze: | arXiv |
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