SPECTRAL RANDOM-WALKS AND LINE BROADENING OF IMPURITY MOLECULES IN ANISING SPIN-GLASS ENVIRONMENT

Transition energy fluctuations in impurity molecules, embedded in an i nhomogeneous environment, are investigated within an Ising spin model of the environment. The spatially distributed impurity molecules are a ssumed to interact with the Ising spin glass through dipole-dipole typ e of interaction. We calculate the fluctuations in the transition ener gies of impurity molecules, for different temperatures and various Isi ng parameters, and find that the spectral distribution of the fluctuat ions follows approximately a 1/f power law. The fluorescence spectra o f the impurity molecules yield microscopic information about domain st ructures in the Ising environment. In the case of large disorder, the distribution of transition energies shows profiles similar to those ob served in single molecule spectroscopy. (C) 1998 American Institute of Physics.