Spectral study of Rhodamine dyes in binary solutions

Electronic absorption and fluorescence spectra of two Rhodamine dyes (Rhodamine B and Rhodamine 6G) in binary solutions are studied in this paper. The excited state dipole moments have been computed using the correlation coefficients obtained by linear solvation energy relationship (LSER) applied to electronic spectra and the values of the dipole moments in the ground state of Rhodamines computed by HyperChem 8.0.6. The nature and the contributions of each type of interactions to the spectral shifts from visible range are established based on solvatochromic analysis.