Correlation between Strain-Field and Electric-Field Effects in Hole-Burning Spectra

The effect of external hydrostatic pressure and electric fields on the absorption lines of dye molecules in amorphous host matrices is discussed in a common framework. For the regime of low pressure and field strength, where only lowest-order terms are important, symmetric expressions for the line shifts are derived, which are connected with the corresponding solvent shift values. In this context the variation of both effects as a function of the position within the inhomogeneous absorption band is discussed. The results of hole-burning experiments on pentacene in PMMA and on a substituted Zn-tetrabenzoporphin in poly(vinyl butyral) show qualitative agreement with the predictions of the solvent shift model.