AN INVESTIGATION OF THE EFFECTS OF 2-LEVEL SYSTEM COUPLING ON SINGLE-MOLECULE LINESHAPES IN LOW-TEMPERATURE GLASSES

A theoretical framework for determining the lineshapes of single molec ules in low temperature glasses is presented. Our methods, in contrast to previous efforts, include coupling between two level systems (TLSs ). This framework is applied to the physical system consisting of the chromophore terrylene embedded in the amorphous host polystyrene. We a nalyze the effect of TLS-TLS coupling on both individual lineshapes an d linewidth histograms. Ourresults indicate that, although TLS-TLS cou pling is certainly capable of producing noticeable changes in individu al spectral lines relative to the uncoupled results, linewidth histogr ams are relatively unaffected by said coupling. An interpretation of t his result is suggested. (C) 1998 American Institute of physics.