title: Comparing the electronic relaxation dynamics of aniline and d(7)-aniline following excitation at 272-238 nm.
abstract: Femtosecond time-resolved photoelectron spectroscopy experiments have been used to compare the electronic relaxation dynamics of aniline and d7-aniline following photoexcitation in the range 272-238 nm. Together with the results of recent theoretical investigations of the potential energy landscape [M. Sala, O. M. Kirkby, S. Guérin and H. H. Fielding, Phys. Chem. Chem. Phys., 2014, 16, 3122], these experiments allow us to resolve a number of unanswered questions surrounding the nonradiative relaxation mechanism. We find that tunnelling does not play a role in the electronic relaxation dynamics, which is surprising given that tunnelling plays an important role in the electronic relaxation of isoelectronic phenol and in pyrrole. We confirm the existence of two time constants associated with dynamics on the 1(1)πσ* surface that we attribute to relaxation through a conical intersection between the 1(1)πσ* and 1(1)ππ* states and motion on the 1(1)πσ* surface. We also present what we believe is the first report of an experimental signature of a 3-state conical intersection involving the 2(1)ππ*, 1(1)πσ* and 1(1)ππ* states.
authors.affiliation: Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK. h.h.fielding@ucl.ac.uk.
authors.forename: Oliver M
authors.initials: OM
authors.lastname: Kirkby
authors.forename: Matthieu
authors.initials: M
authors.lastname: Sala
authors.forename: Garikoitz
authors.initials: G
authors.lastname: Balerdi
authors.forename: Rebeca
authors.initials: R
authors.lastname: de Nalda
authors.forename: Luis
authors.initials: L
authors.lastname: Bañares
authors.forename: Stéphane
authors.initials: S
authors.lastname: Guérin
authors.forename: Helen H
authors.initials: HH
authors.lastname: Fielding