A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Time-resolved momentum imaging of UV photodynamics in structural isomers of iodopropane probed by site-selective XUV ionization
Tekijät: Allum, Felix; Kumagai, Yoshiaki; Nagaya, Kiyonobu; Harries, James R.; Iwayama, Hiroshi; Britton, Mathew; Bucksbaum, Philip H.; Burt, Michael; Brouard, Mark; Downes-Ward, Briony; Driver, Taran; Heathcote, David; Hockett, Paul; Howard, Andrew J.; Lee, Jason W. L.; Liu, Yusong; Kukk, Edwin; McManus, Joseph W.; Milešević, Dennis; Minns, Russell S.; Niozu, Akinobu; Niskanen, Johannes; Orr-Ewing, Andrew J.; Owada, Shigeki; Robertson, Patrick; Rolles, Daniel; Rudenko, Artem; Ueda, Kiyoshi; Unwin, James; Vallance, Claire; Walmsley, Tiffany; Ashfold, Michael N. R.; Forbes, Ruaridh
Kustantaja: Royal Society of Chemistry (RSC)
Julkaisuvuosi: 2025
Journal: Physical Chemistry Chemical Physics
ISSN: 1463-9076
eISSN: 1463-9084
DOI: https://doi.org/10.1039/d5cp02929e
Verkko-osoite: https://doi.org/10.1039/d5cp02929e
The photodynamics of 1- and 2-iodopropane (1 and 2-IP) were studied in a time-resolved scheme incorporating ultraviolet (UV) excitation and extreme ultraviolet (XUV) probing, which initiates photoionization selectively from the I 4d core orbital. UV absorption in the A-band of both isomers leads to prompt C-I bond fission, with significant disposal of internal energy into the propyl radical product. Site-selective ionization enables a range of charge transfer (CT) processes between the nascent highly charged iodine ions and neutral propyl radicals, dependent on the interfragment distance at the instant of ionization. Subtle differences in the dynamics of these CT processes between the two isomers are observed. In 1-IP, the kinetic energies of iodine ions produced by UV photodissociation and subsequent XUV multiple ionization increased notably over the first few hundred femtoseconds, which could be understood in terms of differing gradients along the photodissociation coordinates of the neutral and polycationic states involved in the pump and probe steps, respectively. Led by a recent report of HI elimination in UV photoexcited 2-IP [Todt et al., Phys. Chem. Chem. Phys., 22(46), 27338 (2020)], we also model the most likely signatures of this process in the present experiment, and can identify signal in the 2-IP data (that is absent or significantly weaker in the data from the unbranched 1-IP isomer) that is consistent with such a process occurring on ultrafast timescales.
Julkaisussa olevat rahoitustiedot:
The experiment was performed at SACLA with the approval of JASRI and the program review committee (proposal no. 2021A8038 Forbes). We thank the technical and scientific staff of SACLA for their hospitality and support before and during the beamtime. We thank Luis Ban˜ares and Jesu´s Gonza´lez-Va´zquez for helpful discussions regarding the photodissociation dynamics of 1- and 2-IP. R. F. and F. A. gratefully acknowledge support from the Linac Coherent Light Source, SLAC National Accelerator Laboratory, which is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-76SF00515. Y. K. acknowledges support from JSPS KAKENHI grant no. 20K14427. M. Bu., J. U., and T. W. are grateful to EPSRC for support from EP/ S028617/1. T. W. is additionally thankful to EPSRC for studentship funding and Jesus College, Oxford, for a partial fee scholarship. J. U. is also grateful to the States of Jersey for studentship funding. A. J. O. E., M. Bro, J. W. M., C. V. and D. H. are grateful to the EPSRC for support from Programme grant EP/V026690/1. C. V., D. M. and P. R. also acknowledge the EPSRC for support from Programme Grant EP/T021675/1. D. R. and A. R. were supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, US Department of Energy (grant no. DE-FG02-86ER13491). RSM thanks the EPSRC (EP/X027635/1 and EP/R010609/1) and Leverhulme Trust (RPG2021-257) for funding. B. D. W. thanks the CLF and the University of Southampton for a studentship. F. A. thanks the Alexander von Humboldt Foundation for their support. P. H. B. was supported by the Atomic, Molecular and Optical Sciences Program within the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. A. J. H. was supported Stanford University and the National Science Foundation. J. W. L. L. acknowledges financial support via the Helmholtz-ERC Recognition Award (ERC-RA-0043) of the Helmholtz Association (HGF).
