title: Ultrafast dynamics of aniline in the 294-234 nm excitation range: the role of the πσ∗ state.
abstract: The ultrafast relaxation of jet-cooled aniline was followed by time-resolved ionization, after excitation in the 294-234 interval. The studied range of energy covers the absorption of the two bright ππ∗ excitations, S(1) and S(3), and the almost dark S(2) (πσ∗) state. The employed probe wavelengths permit to identify different ultrafast time constants related with the coupling of the involved electronic surfaces. A τ(1) = 165 ± 30 fs lifetime is attributed to dynamics along the S(2) (πσ∗) repulsive surface. Other relaxation channels as the S(1)→S(0) and S(3)→S(1) internal conversion are also identified and characterized. The work provides a general view of the photophysics of aniline, particularly regarding the role of the πσ∗ state. This state appears as minor dissipation process due to the ineffective coupling with the bright S(1) and S(3) states, being the S(1)→S(0) internal conversion the main non-radiative process in the full studied energy range. Additionally, the influence of the off-resonance adiabatic excitation of higher energy electronic states, particularly S(3), is also observed and discussed.
authors.affiliation: Departamento de Química-Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Bilbao, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Montero
authors.forename: Alvaro Peralta
authors.initials: AP
authors.lastname: Conde
authors.forename: Virginia
authors.initials: V
authors.lastname: Ovejas
authors.forename: Roberto
authors.initials: R
authors.lastname: Martínez
authors.forename: Fernando
authors.initials: F
authors.lastname: Castaño
authors.forename: Asier
authors.initials: A
authors.lastname: Longarte
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D004583:Electrons; D055668:Photochemical Processes; D011789:Quantum Theory
chemical_list: D000814:Aniline Compounds; C023650:aniline