The dynamics of azulene S2 state characterised by femtosecond transient absorption spectroscopy

Year: 1997

Authors: Ciano L., Foggi P., Salvi P.R.

Autors Affiliation: LENS, Largo E. Fermi 2, 50125 Firenze, Italy; Dipartimento di Chimica, via G. Capponi 9, 50121 Firenze, Italy

Abstract: The fast dynamics of the population build-up of S2 state of azulene in ethylene glycol and the following relaxation processes are investigated by transient absorption spectroscopy. The transient spectrum shows bands at 469, 413 and 366 nm. The spectral data are compared to the results of semi-empirical calculations based on the QCFF/PI method. The build-up of S2 population is measured by following the growth in intensity of the main peak (366 nm) as the function of the delay between the pump (340 nm) and the probe (broad continuum). The experimental points are fitted by a single exponential curve with time constant of 300±50 fs. The process is dominated by the fast motions of the solvent cage. The decay of the state occurs with a single exponential mechanism with time constant of 1.06±0.03 ns.

Journal/Review: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

Volume: 105 (2-3)      Pages from: 129  to: 134

More Information: This work has been supported by the Commission of the European Communities under the contract n.GEl *CT 920046. Authors wish to thank Dr P. Bartolini for the help in performing fluorescence decay measurements. Authors acknowledge the contribution of R. Ballerini, M. Giuntini and M. DePas of the LENS technical staff in setting up the transient absorption experimental apparatus.
KeyWords: Electronic dephasing; Excited state dynamics; Transient spectroscopy
DOI: 10.1016/S1010-6030(96)04606-0

Citations: 8
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