Excited-state dynamics of the 1B_u~+,3A_g~-, and 1B_u~- states in a carotenoid molecule by 5-fs absorption spectroscopy

摘要

The time-resolved absorption spectra of all-trans-spirilloxanthin were recorded by the use of extremely stable sub-5-fs pulses covering coherently the main visible range of 520-700 nm. All the theoretically predicted and long-lasting argued states (1B_u~+, 3A_g~-, and 1B_u~- states) were clearly identified for the first time. The spectrum of each component and lifetime were determined without ambiguity by the global fitting method. Their lifetimes were in sequence ～10, 25 ± 2, and 140 ± 30 fs.