Investigation of Rhodamine 6G in oleic acid solution fluorescence under high pressure

Interesting behavior has been observed in the absorption spectra of the solution of Rhodamine 6G [C28H31N2O3Cl] in oleic acid [C18H34O2] [K. Wieja et al., Pressure-induced changes in electronic absorption spectrum in oleic acid, High Press. Res. 30 (2010), pp. 130-134]. Application of high pressures to the solution has caused the reshaping of the absorption spectra curve, and the maximum of absorption has been shifted towards the longer wavelength. One of the most possible explanations of the changes in the absorption spectra is the formation of charge-transfer complexes in the solution. Pressure-induced changes of the VIS absorption spectrum in the mixture of Rhodamine 6G and oleic acid have been observed in comparison with the absorption spectrum of the mixture of Rhodamine 6G in ethanol. Moreover, changes have been observed in the fluorescence spectrum of the examined mixture, which indicated a fluorescent electronic band of a CT complex.