title: Ring-closing and dehydrogenation reactions of highly excited cis-stilbene: ultrafast spectroscopy and structural dynamics.
abstract: The ultrafast dynamics of highly excited cis-stilbene (CS) in a molecular beam is explored using femtosecond time-resolved mass spectrometry and structure-sensitive photoelectron spectroscopy. cis-Stilbene is initially pumped by a 6 eV photon to the 7(1)B state and the reaction is followed by ionization with a time-delayed 3 eV probe pulse. Upon excitation, cis-stilbene rapidly decays to the 3(1)B state, where it undergoes a ring-closing reaction to form 4a,4b-dihydrophenanthrene (DHP). Whereas 14% of the ionized CS molecules dissociate one hydrogen atom to form hydrophenanthrene, the ionized DHP molecules completely dehydrogenate in the ion state to produce hydrophenanthrene and phenanthrene with a 1:1 ratio. We determined the lifetimes of the 7(1)B state and the 3(1)B state of CS to be 167 and 395 fs, respectively.
authors.affiliation: Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Bao
authors.forename: Michael P
authors.initials: MP
authors.lastname: Minitti
authors.forename: Peter M
authors.initials: PM
authors.lastname: Weber