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Non-rigid shell model and novel correlational effects in atomic and molecular systems

Yu. D. Panov·A. S. Moskvin
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Abstract

Direct analytical and numerical calculation show that two-electron atomic configuration can be unstable with respect to a static or dynamic shift of the electron shells. This enables to develop a so called non-rigid shell model for a partial account of the electron correlations within atomic clusters in solids. In a framework of this model a correlated state of two-electron molecular configuration is described by a set of symmetrized shell shifts q^γsimilarly to the well known shell model developed for a description of the lattice dynamics. A set of q^γ-shifts are found after minimization of the energy functional. We present a number of the novel unconventional effects including: i) a correlational mechanism of the local pairing; ii) a correlational (pseudo) Jahn-Teller effect provided by a joint account of the electron shell shifts and conventional nuclear displacements; iii) an appearance of the chiral correlational states. The model allows an introduction of the pseudo-spin formalism and effective "spin-Hamiltonian" for a description of the short- and long-range ordering of non-rigid atomic backgrounds in crystals. Finally, the model can be readily built in the conventional band schemes.

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Yu. D. Panov, A. S. Moskvin. 2000-01-14. Non-rigid shell model and novel correlational effects in atomic and molecular systems. https://arxiv.org/abs/cond-mat/0001213

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