Towards time-resolved, coupled structure-function information on carotenoid excited state processes: X-ray and optical short-pulse double resonance spectroscopy

A novel soft X-ray and optical short-pulse double resonance spectroscopic t echnique tailor-made to elucidate processes involving the optically forbidd en S-1 (2(1)A(g)) state of carotenoids in native biological samples (e,g., photosynthetic antenna complexes) is described. The principle relies on pro bing the near carbon K-edge absorption of the optically excited sample with soft X-rays generated by a laser-induced plasma. A first application conce rns location of the 2(1)A(g) state of beta -carotene in vitro. Further appl ications are proposed. (C) 2001 Elsevier Science B.V. All rights reserved.