Exploring the ultrafast and isomer-dependent photodissociation of iodothiophenes via site-selective ionization

• DOI: 10.1039/d3cp06079a
• Publication Date: 2024-04-05T09:20:50Z
• Authors: Weronika O. Razmus; Felix Allum; James Harries; Yoshiaki Kumagai; Kiyonobu Nagaya; Surjendu Bhattach...; Mathew Britton; Mark Brouard; Philip H. Bucksbaum; Kieran Cheung; Stuart W. Crane; Mizuho Fushitani; Ian Gabalski; Tatsuo Gejo; Aaron Ghrist; David Heathcote; Yasumasa Hikosaka; Akiyoshi Hishikawa; Paul Hockett; Ellen Jones; Edwin Kukk; Hiroshi Iwayama; Huynh V. S. Lam; Joseph W. McManus; Dennis Milesevic; Jochen Mikosch; Shinichirou Minemoto; Akinobu Niozu; Andrew J. Orr-Ewing; Shigeki Owada; Daniel Rolles; Artem Rudenko; Dave Townsend; Kiyoshi Ueda; James Unwin; Claire Vallance; Anbu Venkatachalam; Shin-ichi Wada; Tiffany Walmsley; Emily M. Warne; Joanne L. Woodhouse; Michael Burt; Michael N. R. Ash...; Russell S. Minns; Ruaridh Forbes
• Keywords: Coulomb explosion; Photoexcitation; Extreme ultraviolet

C-I bond extension and fission following ultraviolet (UV, 262 nm) photoexcitation of 2- 3-iodothiophene is studied using ultrafast time-resolved extreme (XUV) ionization in conjunction with velocity map ion imaging. The photoexcited molecules eventual I atom products are probed by site-selective at the 4d edge intense XUV pulses, which induce multiple charges initially localized to iodine atom. At separations below critical distance for charge transfer (CT), can redistribute around molecule leading Coulomb explosion charged fragments high kinetic energy. greater separations, beyond distance, CT no longer possible measured energies atoms report on neutral dissociation process. time momentum resolved measurements allow determination timescales respective product energy distributions both isomers, interpreted terms rival 'direct' 'indirect' pathways. compared a classical over barrier model, reveals that onset indirect process delayed ∼1 ps relative direct kinetics two processes show discernible difference between parent but branching channels isomer dependencies. yield from nm photolysis (