摘要
We present a comprehensive study, by femtosecond pump-probe spectroscopy, of excited state dynamics in a polyene that approaches the infinite chain limit. By excitation with sub-10-fs pulses resonant with the 0-0 S-0 -> S-2 transition, we observe rapid loss of stimulated emission from the bright excited state S-2, followed by population of the hot S-1 state within 150 fs. Vibrational cooling of S-1 takes place within 500 fs and is followed by decay back to S-0 with 1 ps time constant. By excitation with excess vibrational energy we also observe the ultrafast formation of a long-living absorption, that is assigned to the triplet state generated by singlet fission.
- 出版日期2010-7-19