Shift of emission band upon the excitation at the long wavelength absorption edge. III. Temperature dependence of the shift and correlation with the time dependent spectral shift

Abstract

The edge‐excitation red shift previously observed for quinine and related compounds has been shown to exist also for 8‐anilinonaphthalene‐1‐sulfonic acid. The excitation energy dependent spectral shift observed here and the time dependent spectral shift observed by Chakrabarti and Ware have been interpreted satisfactorily in terms of one and the same mechanism. The previously suggested mechanism of the red shift in which the solute–solvent interaction plays an essential role is thus supported. The solvent reorientation relaxation time has been estimated from two different sets of experimental data, one concerned with the excitation energy dependent shift and the other with the time dependent shift. The estimated relaxation times are shown to be entirely different from the dielectric relaxation times of the solvent.