Singlet internal conversion processes in the order of 1Bu+→3Ag-→1Bu-→2Ag-→1Ag- in all-trans-spheroidene and lycopene as revealed by subpicosecond time-resolved Raman spectroscopy

Singlet internal conversion processes in carotenoids with the number of conjugated double bonds, n = 10 and 11, were identified by subpicosecond time-resolved Raman spectroscopy. The time constant in each step of internal conversion reflects the energy gap between the relevant states.