Photoluminescence of L-cystine and taurine molecules

Abstract This paper describes the measurement techniques and results obtained by optical spectroscopy under photon excitation of aliphatic sulfur-containing amino acid molecules in a microcrystalline state (powder). The photoluminescence (PL) spectra of L-cystine and taurine were investigated for the first time in the 400–700 nm wavelength range upon excitation by photons with energies of 3.26–4.51 eV. The measured PL spectra revealed emission from CH radicals. The PL spectra of taurine also exhibited emission from the hydroxyl radical OH. The dependence of the PL spectra (structure, emission intensity, peak positions) on the excitation photon energy was studied. It was shown that the presence of a disulfide bond in the L-cystine molecule has a decisive influence on the formation of its PL spectrum.