title: Ultrafast Dissociation Dynamics of 2-Ethylpyrrole.
abstract: To explore the effects of ring substitution on dissociation dynamics, the primary photochemistry of 2-ethylpyrrole was explored using ultrafast ion imaging techniques. Photoexcitation to the S1state, a πσ* state, in the range from 238 to 265 nm results in cleavage of the N-H bond with an H atom appearance lifetime of ca. 70 fs. The insensitivity of this lifetime to photon energy, combined with a small kinetic isotope effect, suggests that tunneling does not play a major role in N-H bond cleavage. Total kinetic energy release spectra reveal modest vibrational excitation in the radical counter-fragment, increasing with photon energy. At wavelengths less than or equal to 248 nm, an additional low kinetic energy H atom loss mechanism becomes available with an appearance lifetime of ∼1.5 ps, possibly due to the population of higher-lying1ππ* states.
authors.affiliation: Department of Chemistry, University of Warwick , Library Road, Coventry CV4 7AL, United Kingdom.
authors.forename: Neil C
authors.identifier: http://orcid.org/0000-0002-3619-8915
authors.initials: NC
authors.lastname: Cole-Filipiak
authors.affiliation: Department of Chemistry, University of Warwick , Library Road, Coventry CV4 7AL, United Kingdom.|Department of Physics, University of Warwick , Gibbet Hill Road, Coventry CV4 7AL, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Staniforth
authors.affiliation: Department of Chemistry, University of Warwick , Library Road, Coventry CV4 7AL, United Kingdom.
authors.forename: Natércia
authors.initials: N
authors.lastname: D N Rodrigues
authors.affiliation: AILES beamline, L'Orme des Merisiers, Synchrotron SOLEIL , Saint Aubin, BP 48, 91192 Gif sur Yvette Cedex, France.
authors.forename: Yoann
authors.initials: Y
authors.lastname: Peperstraete
authors.affiliation: Department of Chemistry, University of Warwick , Library Road, Coventry CV4 7AL, United Kingdom.
authors.forename: Vasilios G
authors.initials: VG
authors.lastname: Stavros