Asymmetric structure for the excited S1 state of 2,2'-bipyridine evidenced by picosecond time-resolved resonance Raman experiments and ab initio calculation

V. de Waele (1, 2) , G. Buntinx (1, 2) , J.P. Flament (3) , O. Poizat (1, 2)

1 LASIRE - Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516
2 CERLA - Centre d'Etudes et de Recherches Lasers et Applications
3 PhLAM - Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523

The combination of ab initio calculation using the CIS method and experimental vibrational data from picosecond time-resolved Raman measurements leads to a confident picture of the structure of the lowest excited singlet state S1 (n*) of 2,2-bipyridine. The calculated structure is asymmetric with two dissimilar pyridyl moieties. It can be understood as resulting from a confinement of the excitation in one of the pyridyl rings, breaking the initial ground-state symmetry. The reliability of this structure is attested by good agreement between the derived theoretical vibrational data and the experimental Raman spectra. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005

V. de Waele, G. Buntinx, J.P. Flament, O. Poizat. Asymmetric structure for the excited S1 state of 2,2'-bipyridine evidenced by picosecond time-resolved resonance Raman experiments and ab initio calculation. International Journal of Quantum Chemistry, 2005, 104, pp.794-807. ⟨10.1002/qua.20599⟩. ⟨hal-00268688⟩