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arXiv · 0811.4583

Dependence of response functions and orbital functionals on occupation numbers

S. Kurth·C. R. Proetto·K. Capelle
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Abstract

Explicitly orbital-dependent approximations to the exchange-correlation energy functional of density functional theory typically not only depend on the single-particle Kohn-Sham orbitals but also on their occupation numbers in the ground state Slater determinant. The variational calculation of the corresponding exchange-correlation potentials with the Optimized Effective Potential (OEP) method therefore also requires a variation of the occupation numbers with respect to a variation in the effective single-particle potential, which is usually not taken into account. Here it is shown under which circumstances this procedure is justified.

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S. Kurth, C. R. Proetto, K. Capelle. 2008-11-27. Dependence of response functions and orbital functionals on occupation numbers. https://arxiv.org/abs/0811.4583

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