title: Unusual quantum interference in the S1 state of DABCO and observation of intramolecular vibrational redistribution.
abstract: In this paper we report an experimental study of the time-resolved response of the molecule 1,4-diazabicyclo[2.2.2]octane (DABCO) to 266.3 nm electronic excitation of the S(1) state with a femtosecond laser. Rotational decoherence and vibrational oscillation within the S(1) state are observed. We performed state-of-the-art ab initio calculations on the ground and low electronic states of the neutral molecule and the cation, which assist in the assignment of the observed photoelectron signals. Using our theoretical and spectroscopic data, the experimental findings are interpreted in terms of an unusual quantum interference between two different vibrational modes, with only the nu = 1 level of each mode being populated.
authors.affiliation: Laboratoire Francis Perrin, CNRS URA 2453, CEA, IRAMIS, Service des Photons Atomes et Molécules, F-91191 Gif/Yvette, France. lionel.poisson@cea.fr
authors.forename: Lionel
authors.initials: L
authors.lastname: Poisson
authors.forename: Raman
authors.initials: R
authors.lastname: Maksimenska
authors.forename: Benoît
authors.initials: B
authors.lastname: Soep
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Mestdagh
authors.forename: David H
authors.initials: DH
authors.lastname: Parker
authors.forename: Mama
authors.initials: M
authors.lastname: Nsangou
authors.forename: Majdi
authors.initials: M
authors.lastname: Hochlaf
mesh_terms: D007834:Lasers; D010879:Piperazines / Q000737:chemistry*; D011789:Quantum Theory; D013997:Time Factors; D014732:Vibration
chemical_list: D010879:Piperazines; C007306:triethylenediamine