Minimal distance between chromophore and two-level systems in amorphous solids: effect on photon echo and single molecule spectroscopy data

We investigated the possible effect of the existence of minimal cutoff distance between two-level system (TLS) and chromophore molecule in glasses on the low-temperature photon echo (PE) and single molecule spectroscopy (SMS) data. Our analysis was based on the tunneling TLS and sudden jump models of glasses. The PE data were considered using the stochastic model of PE in low-temperature glasses as modified by us. Analysis of SMS data was based on the theory of SM line shapes developed by Geva and Skinner [J. Phys. Chem. 101 (1997) 8920]. It was shown that the existence of a minimal approach distance between TLS and chromophore centers results in noticeable changes of the calculated PE and SMS data. These changes increase with increasing of temperature. (C) 2002 Elsevier Science B.V. All rights reserved.