2007/03/22 by C. Medrano, Medrano, C., M. Georgiev +1
Materials Science · Physics and Astronomy · #Advanced Chemical Physics Studies #Physics of Superconductivity and Magnetism #Solid-state spectroscopy and crystallography #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/0703592
23 pages including 3 tables and 3 figures, all pdf format
arxiv created 2007/03/22 · arxiv updated 2009/12/01
This paper is aimed at presenting a simple vibronic model for describing the dipolar reorientation in crystals by means of reaction rate theory. The Hamiltonian of an isolated dipole is simplified so as to render the problem solvable. Depending on the crossover splitting the dipoles may reorientate adiabatically with a high electron-transfer expectancy or exhibit low reorientation rates due to low expectancy. An important quantity to distinguish between adiabatic dipoles behaving classically and ones reorientating by means of quantum-mechanical tunneling is Christov's characteristic temperature which is found to relate to the barrier height and crossover splitting. ITC data on impurity-vacancy dipoles in Eu-doped alkali halides are reanalyzed.