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arXiv · 1802.02144

Restoring size consistency of approximate functionals constructed from the adiabatic connection

S. Vuckovic·P. Gori-Giorgi·F. Della Sala·E. Fabiano
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Abstract

Approximate exchange-correlation functionals built by modeling in a non-linear way the adiabatic connection (AC) integrand of density functional theory have many attractive features, being virtually parameters-free and satisfying different exact properties, but they also have a fundamental flaw: they violate the size-consistency condition, crucial to evaluate interaction energies of molecular systems. We show that size consistency in the AC-based functionals can be restored in a very simple way at no extra computational cost. Results on a large set of benchmark molecular interaction energies show that functionals based on the interaction strength interpolation approximations are significantly more accurate than the second-order perturbation theory.

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S. Vuckovic, P. Gori-Giorgi, F. Della Sala, E. Fabiano. 2018-02-06. Restoring size consistency of approximate functionals constructed from the adiabatic connection. https://doi.org/10.1021/acs.jpclett.8b01054

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