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Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Ultrafast photophysics of the isolated indole molecule
Raúl Montero1, Álvaro Peralta Conde, Virginia Ovejas
1Departamento de Química-Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain.
Abstract:
The relaxation dynamics of the isolated indole molecule has been tracked by femtosecond time-resolved ionization. The excitation region explored (283-243 nm) covers three excited states: the two ππ* L(b) and L(a) states, and the dark πσ* state with dissociative character. In the low energy region (λ > 273 nm) the transients collected reflect the absorption of the long living L(b) state. The L(a) state is met 1000-1500 cm(-1) above the L(b) origin, giving rise to an ultrafast lifetime of 40 fs caused by the internal conversion to the lower L(b) minimum through a conical intersection. An additional ~400 fs component, found at excitation wavelengths shorter than 263 nm, is ascribed to dynamics along the πσ* state, which is likely populated through coupling to the photoexcited L(a) state. The study provides a general view of the indole photophysics, which is driven by the interplay between these three excited surfaces and the ground state.
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