Singlet internal conversion processes in the order of IBu+- 3A(g)(-)- IBu-- 2A(g)(-)- IA(g)(-) in all-trans-spheroidene and lycopene as revealed by subpicosecond time-resolved Raman spectroscopy

摘要

Key Raman lines ascribable to the 1B(u)(+), 3A(g)(-), 1B(u)(-) and 2A(g)(-) states were identified in the subpicosecond time-resolved Raman spectra of spheroidene and lycopene having 10 and I I conjugated double bonds, respectively. The sequential rise-and-decay of the key Raman lines showed the internal conversion processes of 1B(u)(+) -> 3A(g)(-) -> 1B(u)(-) -> 2A(g)(-) -> 1A(g)(-) (ground). The time constant in each step of internal conU version reflects the energy gap between the relevant states that had been determined by measurement of resonance - Raman excitation profiles [K. Furuichi, T. Sashima, Y. Koyama, Chem. Phys. Lett. 356 (2002) 547]. (c) 2006 Elsevier B.V. All rights reserved.