MULTIWELL POTENTIALS OF ENDOHEDRAL COMPLEXES OF ICOSAHEDRAL SYMMETRY

We examine multiwell potentials that correspond to the displacements o f off-center ions in complexes with icosahedral symmetry (dodecahedron s, icosahedrons, fullerenes, etc.) along symmetry directions (toward v ertices, midpoints of edges, and centers of faces). An expression is d erived for an effective Hamiltonian, which describes the behavior of e ndohedral complexes with off-center ions placed in external electric f ields of arbitrary strength and orientation. We find the eigenvalues o f this Hamiltonian and calculate the intensities of the lines of all p ossible transitions between tunneling levels. We also predict and anal yze the spectra of paraelectric resonances in the absence of an extern al static electric field (zero-field resonances) and in the presence o f such a field. Finally, we provide recommendations for detecting thes e effects and discuss the specific features of the effects and the pos sibility of studying them. (C) 1998 American Institute of Physics.