title: Time-resolved photoelectron spectroscopy of the CH(3)I B(1)E 6s [2] state.
abstract: The predissociation dynamics of the vibrationless level of the 6s (B (2)E) Rydberg state of CH(3)I was studied by femtosecond-resolved velocity map imaging of photoelectrons. By monitoring the decay of the CH(3)I(+) produced by photoionizing the B state, the predissociation lifetime was measured to be 1310 ± 70 fs. Photoelectron spectra were recorded as a function of the excitation scheme (one or two photons to the B state), and as a function of the ionizing wavelength. All of these photoelectron spectra show a simple time dependence that is consistent with the decay time of the CH(3)I(+) ion signal. The photoelectron angular distributions for the ionization of the B state depend on the excitation scheme and the ionizing wavelength, and show a strong dependence on the vibrational modes excited in the resulting CH(3)I(+). At long delays, the photoelectron spectra are characterized by photoionization of the I((2)P(1/2)) fragment formed by predissociation of the B state.
authors.affiliation: Université de Toulouse, UPS, 118 route de Narbonne, F-31062 Toulouse, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Thiré
authors.forename: Raluca
authors.initials: R
authors.lastname: Cireasa
authors.forename: Valerie
authors.initials: V
authors.lastname: Blanchet
authors.forename: Steven T
authors.initials: ST
authors.lastname: Pratt