Decay of mesoscopically localized vibrations in porous materials

The low-temperature decay of a vibrational eigenstate of a crystalline mesoscopic particle surrounded by other such particles of approximately the same size is considered. The decay time is determined by the anharmonicity and the coupling between adjacent mesoscopic particles. Under some limiting conditions for particles of a typical size of 50 Angstrom the decay time at low temperatures can be several milliseconds. (C) 1998 American Institute of Physics. [S0021-3640(98)01001-9].