Gas-phase electronic spectra of two substituted benzene cations: phenylacetylene+ and 4-fluorostyrene+.
The visible spectra of phenylacetylene+ and 4-fluorostyrene+ have been measured by laser photodissociation spectroscopy. The observed vibronic systems were assigned to the B2A'' <-- X2A'' and C2B1 <-- X2B1 electronic transition in the 4-fluorostyrene+ and phenylacetylene+ cations, respectively. Two methods were employed and compared: a resonant multiphoton dissociation scheme of the bare cations and a resonant photodissociation technique applied to the chromophore+-argon n=1,2 ionic complexes. The latter approach allowed the intrinsic profile to be resolved, revealing different intramolecular dynamical behavior. Their electronic relaxation has been rationalized in terms of an apparent energy gap law for the benzene derivative cations.
Pino
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Laboratoire de Photophysique Moléculaire, CNRS, bâtiment 210 Université Paris-Sud, F-91405 Orsay Cedex, France.
Douin
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Boudin
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Bréchignac
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