Revisiting the off-center impurity problem: Reorientational rate by mathieu functions

P.C. Petrova, M.D. Ivanovitch, M. Georgiev, M.S. Mladenova, G. Baldacchini, R.-M. Montereali, U.M. Grassano, A. Scacco

Research output: Contribution to journalArticle


We revisit the quantum mechanical problem of an off-centered impurity in an alkali halide crystal by means of the Pseudo-Jahn-Teller Effect. We confirm that while an impurity may be displaced off-center by virtue of first- order vibronic mixing, reorientational barriers hindering the rotation of an off-centered impurity around a lattice site arise by third-order mixing. The eigenvalue equation of a hindered rotation in-plane is Mathieu's equation. We use the exact eigenstates and eigenvalues to derive a reorientational rate. The rate is compared with available paraelectric data on a Li impurity in KCl.
Original languageEnglish
Pages (from-to)377 - 380
Number of pages4
JournalMaterials Science Forum
Publication statusPublished - 1997
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Petrova, P. C., Ivanovitch, M. D., Georgiev, M., Mladenova, M. S., Baldacchini, G., Montereali, R-M., ... Scacco, A. (1997). Revisiting the off-center impurity problem: Reorientational rate by mathieu functions. Materials Science Forum, 239-241, 377 - 380.