INVESTIGATION OF LOW-TEMPERATURE LINE BROADENING MECHANISMS IN ORGANIC AMORPHOUS SOLIDS WITH PHOTON-ECHO, HOLE-BURNING AND SINGLE-MOLECULE SPECTROSCOPY

We present the first comparative analysis of spectral data obtained at low temperatures with three different highly selective techniques: tw o-pulse photon echo (2PE), hole-burning (HB) and single-molecule spect roscopy (SMS) of a polyisobutylene glass (PIB) doped with tetra-tert-b utylterrylene (TBT). Our 2PE- and MB-experiments are compared with lit erature data [Tittel et al., J. Lumin. 64 (1995) 1] obtained by SMS. I t is found that the linewidth measured by HE is significantly larger t han the mean of the linewidth distribution obtained by SMS. We conclud e that a T-2-dispersion plays an important role in the formation of th e linewidth dispersion in TBT/PIB. (C) 1998 Elsevier Science B.V. All rights reserved.