Time-resolved resonance Raman spectroscopy of carotenoids in Triton X-100 micellar solution

Abstract

Nanosecond time-resolved resonance Raman spectroscopy has been carried out on all-trans β-carotene, canthaxanthin and zeaxanthin in their lowest excited triplet states, generated by energy transfer from triplet anthracene, in aqueous 2% Triton X-100 micelles. This work reports, for the first time, the Raman spectra of triplet carotenoids in micelles and under these conditions the spectra are very similar to those previously reported in benzene. Thus the carotenoid is either insensitive to environment, or the micelle core is strongly hydrophobic: this result has implications for the conformation of the carotenoid triplet state. The resonance Raman spectrum of the triplet state of γ-carotene in chloroform is also reported.