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arXiv · 2303.06400

1-matrix functional for long-range interaction energy of two hydrogen atoms

Jerzy Cioslowski·Christian Schilling·Rolf Schilling
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Abstract

The leading terms in the large-$R$ asymptotics of the functional of the one-electron reduced density matrix for the ground-state energy of the H$_2$ molecule with the internuclear separation $R$ is derived thanks to the solution of the phase dilemma at the $R \to \infty$ limit. At this limit, the respective natural orbitals (NOs) are given by symmetric and antisymmetric combinations of "half-space" orbitals with the corresponding natural amplitudes of the same amplitudes but opposite signs. Minimization of the resulting explicit functional yields the large-$R$ asymptotics for the occupation numbers of the weakly occupied NOs and the $C_6$ dispersion coefficient. The highly accurate approximates for the radial components of the $p$-type "half-space" orbitals and the corresponding occupation numbers (that decay like $R^{-6}$), which are available for the first time thanks to the development of the present formalism, have some unexpected properties.

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Jerzy Cioslowski, Christian Schilling, Rolf Schilling. 2023-03-11. 1-matrix functional for long-range interaction energy of two hydrogen atoms. https://doi.org/10.1063/5.0139897

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