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Updated: Jun 4, 2026

Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional π-conjugate Systems
Published on: February 10, 2020
Ring-closing and dehydrogenation reactions of highly excited cis-stilbene: ultrafast spectroscopy and structural
Jie Bao1, Michael P Minitti, Peter M Weber
1Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
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.
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