Direct observation of S2-S1 internal conversion in pyrene by femtosecond transient absorption
Anno: 1999
Autori: Neuwahl F.V.R., Foggi P.
Affiliazione autori: LENS, Largo E. Fermi 2, 50125 Florence, Italy; Dipartimento di Chimica, via G. Capponi 9, 50121 Florence, Italy
Abstract: UV pulses of 100 fs at 340 nm are utilised to excite pyrene to the vibrationally cold S2 state. Population and depopulation processes occurring in the S2 state are investigated by transient absorption spectroscopy with a white continuum probe. In the first 400 fs after excitation it is possible to measure the growth and disappearance of a band at 585 nm which is assigned to the S14?S2 transition. As a consequence of the internal conversion process from S2 to S1 state, the disappearance of the 585 nm band and the growth of the transient spectrum due to Sn?S1 transitions can be observed. Kinetic measurements of the S2 decay and S1 growing signals provide an estimate of the rate of internal conversion which occurs with a time constant of 150±50 fs.
Giornale/Rivista: LASER CHEMISTRY
Volume: 19 (1-4) Da Pagina: 375 A: 379
Parole chiavi: Femtosecond; Internal conversion; Pyrene; Transient absorptionDOI: 10.1155/1999/37692Citazioni: 34dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2024-04-28Riferimenti tratti da Isi Web of Knowledge: (solo abbonati) Link per visualizzare la scheda su IsiWeb: Clicca quiLink per visualizzare la citazioni su IsiWeb: Clicca qui