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arXiv · 0710.0650

Off-center impurity in alkali halides: reorientation, electric polarization and pairing to F center. II. In-plane rotation and polarizability

G. Baldacchini·R. M. Montereali·U. M. Grassano·A. Scacco·P. Petrova·M. Mladenova·M. Ivanovich·M. Georgiev
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Abstract

Because of its inherent 2-D character, the eigenvalue equation for the hindered rotation around a normal cation site of an off-center impurity nearest-neighboring an F center is the well-known Mathieu equation. We present an overview of literature data on Mathieu's periodic functions providing exact solutions to the Li+ reorientational problem. We compare them with bottom-well approximating solutions by harmonic-oscillator functions at an effective vibrational frequency renormalized by both first- and third- order electron-mode coupling. We finally discuss the in-plane inversion polarizability of an off-center impurity assumed to form a dipole-dipole coupling with a nearby F center.

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G. Baldacchini, R. M. Montereali, U. M. Grassano, A. Scacco, P. Petrova, M. Mladenova, M. Ivanovich, M. Georgiev. 2007-10-02. Off-center impurity in alkali halides: reorientation, electric polarization and pairing to F center. II. In-plane rotation and polarizability. https://arxiv.org/abs/0710.0650

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