Two-dimensional sketches of a hypothetical glass which is composed of two types of atoms (see Ref. 31) with quasilocalized low-frequency vibrational modes and impurity chromophores. Two possible situations regarding the relative positions of SM and LFMs are presented: (a) The chromophore (big circle) is located inside a LFM (hatched circles). (b) The chromophore is located close to two LFMs (gray circles).
Spectral trails (left panel) and corresponding sum spectra (right panel) for the same single tetra-tert-butylterrylene molecule in amorphous polyisobutylene at different temperatures. The spectra feature line broadening, line splitting, and a blueshift with increasing temperatures. The gray level of each point in the 2D plots is proportional to signal intensity. The horizontal axes correspond to the laser frequency detuning, the vertical axes (in the 2D plots) correspond to the number of scans ( for all plots).
This example demonstrates the procedure for determining the width of the spectral peaks in the case when a single-molecule spectrum consists of several overlapped lines. This spectrum corresponds to the example of Fig. 2 at . The circles correspond to the experimental data, the dashed lines show the fits of the peaks by Lorentzians, and the solid line represents the total fit.
Left panel: Linewidth and spectral shift as measured for the same single molecule of tetra-tert-butylterrylene in polyisobutylene at different temperatures. Right panel: Sum spectra of this molecule at five selected temperatures.
Experimental temperature dependences of the spectral linewidth for four single tetra-tert-butylterrylene molecule in polyisobutylene (symbols) and homogeneous linewidth as measured with the photon echo technique for the same system (solid line; Ref. 28). Note the logarithmic axes. The dotted and dashed line represent the fits of Eq. (1) to the data of molecules “3” and “4,” respectively. The parameters of all the fits are listed in Table I. The insert shows the temperature dependence of the linewidth for molecule 4 in a broader temperature range. The lines in the insert show the contributions of two-level systems (solid line) and quasilocalized low-frequency vibrational modes (dashed line).
Parameters of the experimental temperature dependences of the linewidths for nine single tetra-tert-butylterrylene molecules in polyisobutylene and of the homogeneous linewidth as measured with the photon echo technique for the same system (see Ref. 28). The temperature dependences of the linewidths for molecules 1–4 are shown in Fig. 5.
Article metrics loading...
Full text loading...