Determination of excited state dipole moments in solution via thermochromic methods.

The method basically combines the existing ideas of excited state dipole moment determination via thermochromic fluorescence spectroscopy with the determination of the solvent cavity volume via concentration dependent density measurements of the solution densities at different weight fractions. Additionally, the determination of the cavity volume in dependence of the solvent temperature is included here, which provides a better accuracy of the excited state dipole moment determination. With this step two major sources of errors are eliminated: the use of the very imprecise Onsager radius and the assumption, that the cavity size is temperature independent.•Thermochromic absorption and fluorescence spectroscopy.•Cavity volume determination by density measurements.•Temperature dependent cavity volume determination.