2. Ultra-Fast-VUV Photoemission Study of UV Excited 2-NitrophenolA. Ciavardini, Marcello Coreno, Carlo Callegari, C. Spezzani, Giovanni De Ninno, Barbara Ressel, Cesare Grazioli, Monica de Simone, Antti Kivimak̈i, Paolo Miotti, Fabio Frassetto, Luca Poletto, Petra Rudolf, Simona Fornarini, Marco Pezzella, Enrico Bodo, Susanna Piccirillo, 2019, original scientific article Abstract: The initial deactivation pathways of gaseous 2-nitrophenol excited at 268 nm were investigated by time-resolved photoelectron spectroscopy (TRPES) with femtosecond-VUV light, produced by a monochromatized high harmonic generation source. TRPES allowed us to obtain new, valuable experimental information about the ultrafast excited-state dynamics of 2-nitrophenol in the gas phase. In accord with recent ab initio on-the-fly nonadiabatic molecular dynamic simulations, our results validate the occurrence of an ultrafast intersystem crossing leading to an intermediate state that decays on a subpicosecond time scale with a branched mechanisms. Two decay pathways are experimentally observed. One probably involves proton transfer, leading to the most stable triplet aci-form of 2-nitrophenol; the second pathway may involve OH rotation. We propose that following intersystem crossing, an ultrafast fragmentation channel leading to OH or HONO loss could also be operative.
Keywords: Ultrafast photoemission, nitrophenol
Published in RUNG: 12.02.2019; Views: 5020; Downloads: 0
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