Transient absorption and vibrational relaxation dynamics of the lowest excited singlet state of pyrene in solution

Year: 1995

Authors: Foggi P., Pettini L., Sànta I., Righini R., Califano S.

Autors Affiliation: Institute of Physics, Janus Pannonius University, Pécs, Hungary

Abstract: The spectrum of highly excited electronic states of pyrene in n-octane solution and the relaxation processes in the S1 singlet state are investigated by femtosecond transient absorption spectroscopy. Three different UV excitation wavelengths (360, 307, and 290 nm) are utilized to excite the molecule at the edge of the S1 ? S0 transition and to higher Sn ? S0 transitions. The buildup of S1 population has been observed to be completed in the first 2 ps, with a time constant of 300-400 fs, depending on the excitation wavelength. The evolution of the absorption spectra on a larger time scale is attributed to the vibrational cooling in the S1 state; its rate corresponds to an exponential relaxation with time constant of about 4 ps. The evidence of the formation of pyrene excimer at long time delays in highly concentrated solutions is reported.

Journal/Review: JOURNAL OF PHYSICAL CHEMISTRY

Volume: 99 (19)      Pages from: 7439  to: 7445

KeyWords: Emission-spectra; Excitation
DOI: 10.1021/j100019a029

Citations: 59
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