Temperature and laser intensity effects on the highly resolved fluorescence spectra of the model compound tetracene in crystalline and in amorphous cryogenic solid solutions have been investigated.
In crystalline solid solutions, using lamp and selective laser excitation, the spectra show a strongly temperature dependent height, width and position of the narrow lines. Hence, accurate temperature control and stability are required for reliable identification and quantification. In amorphous solutions under laser excitation also the height and width of the narrow lines strongly depend on temperature; the line positions, however, are independent of the temperature and the choice of the matrix material.
The effect of the laser intensity on fluorescence line-narrowed spectra has been studied for tetracene in amorphous glassy and polymer matrices. It appears that already at relatively low laser powers the narrow lines show a nonlinear dependence of their fluorescence intensity, in particular when excitation is performed in regions with large absorption cross sections.
Moreover, attention will be paid to the temperature- and laser intensity dependence of hole-burning effects in laser excited spectra in amorphous matrices.