eprintid: 10190358 rev_number: 14 eprint_status: archive userid: 699 dir: disk0/10/19/03/58 datestamp: 2024-04-09 13:31:09 lastmod: 2024-04-10 20:34:58 status_changed: 2024-04-09 13:31:09 type: article metadata_visibility: show sword_depositor: 699 creators_name: Lau, Nicholas A creators_name: Ghosh, Deborin creators_name: Bourne-Worster, Susannah creators_name: Kumar, Rhea creators_name: Whitaker, William A creators_name: Heitland, Jonas creators_name: Davies, Julia A creators_name: Karras, Gabriel creators_name: Clark, Ian P creators_name: Greetham, Gregory M creators_name: Worth, Graham A creators_name: Orr-Ewing, Andrew J creators_name: Fielding, Helen H title: Unraveling the Ultrafast Photochemical Dynamics of Nitrobenzene in Aqueous Solution ispublished: inpress divisions: UCL divisions: B04 divisions: C06 divisions: F56 note: Copyright © 2024 The Authors. This publication is licensed under CC-BY 4.0. abstract: Nitroaromatic compounds are major constituents of the brown carbon aerosol particles in the troposphere that absorb near-ultraviolet (UV) and visible solar radiation and have a profound effect on the Earth’s climate. The primary sources of brown carbon include biomass burning, forest fires, and residential burning of biofuels, and an important secondary source is photochemistry in aqueous cloud and fog droplets. Nitrobenzene is the smallest nitroaromatic molecule and a model for the photochemical behavior of larger nitroaromatic compounds. Despite the obvious importance of its droplet photochemistry to the atmospheric environment, there have not been any detailed studies of the ultrafast photochemical dynamics of nitrobenzene in aqueous solution. Here, we combine femtosecond transient absorption spectroscopy, time-resolved infrared spectroscopy, and quantum chemistry calculations to investigate the primary steps following the near-UV (λ ≥ 340 nm) photoexcitation of aqueous nitrobenzene. To understand the role of the surrounding water molecules in the photochemical dynamics of nitrobenzene, we compare the results of these investigations with analogous measurements in solutions of methanol, acetonitrile, and cyclohexane. We find that vibrational energy transfer to the aqueous environment quenches internal excitation, and therefore, unlike the gas phase, we do not observe any evidence for formation of photoproducts on timescales up to 500 ns. We also find that hydrogen bonding between nitrobenzene and surrounding water molecules slows the S1/S0 internal conversion process. date: 2024-04-04 date_type: published publisher: American Chemical Society (ACS) official_url: http://dx.doi.org/10.1021/jacs.3c13826 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2266314 doi: 10.1021/jacs.3c13826 lyricists_name: Fielding, Helen lyricists_name: Worth, Graham lyricists_id: HHFIE17 lyricists_id: GWORT12 actors_name: Fielding, Helen actors_id: HHFIE17 actors_role: owner full_text_status: public publication: Journal of the American Chemical Society citation: Lau, Nicholas A; Ghosh, Deborin; Bourne-Worster, Susannah; Kumar, Rhea; Whitaker, William A; Heitland, Jonas; Davies, Julia A; ... Fielding, Helen H; + view all <#> Lau, Nicholas A; Ghosh, Deborin; Bourne-Worster, Susannah; Kumar, Rhea; Whitaker, William A; Heitland, Jonas; Davies, Julia A; Karras, Gabriel; Clark, Ian P; Greetham, Gregory M; Worth, Graham A; Orr-Ewing, Andrew J; Fielding, Helen H; - view fewer <#> (2024) Unraveling the Ultrafast Photochemical Dynamics of Nitrobenzene in Aqueous Solution. Journal of the American Chemical Society 10.1021/jacs.3c13826 <https://doi.org/10.1021/jacs.3c13826>. (In press). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10190358/3/lau-et-al-2024-unraveling-the-ultrafast-photochemical-dynamics-of-nitrobenzene-in-aqueous-solution.pdf document_url: https://discovery.ucl.ac.uk/id/eprint/10190358/2/NB-SI-final.pdf