Eur. Phys. J. B 28, 271-276 (2002)
https://doi.org/10.1140/epjb/e2002-00229-3

High-order vibrational relaxation: a nonperturbative theory

Institute of Physics, University of Tartu, Riia 142, 51014 Tartu, Estonia

Corresponding author: ^a helle@eeter.fi.tartu.ee

Received: 2 May 2002
Published online: 31 July 2002

Abstract

A nonperturbative theory of the multiphonon relaxation of a localized vibrational mode, caused by a high-order anharmonic interaction with the nearest atoms of the crystal lattice, is proposed. It relates the rate of the process to the positive frequency part of the time-dependent non-stationary displacement correlation function of atoms. The nonlinear integral equation for this function is derived and solved numerically. We have found that the rate exhibits a critical behavior: it sharply increases near a specific (critical) value(s) of the interaction; the corresponding dependence is characterized by the critical index , where k is the number of the created phonons.