Monitoring the Evolution of Relative Product Populations at Early Times during a Photochemical Reaction
J. Pedro F. Nunes, Lea M. Ibele, Shashank Pathak, Andrew Attar, Surjendu Bhattacharyya, Rebecca Boll, Kurtis Borne, Martin Centurion, Benjamin Erk, Ming‐Fu Lin, Ruaridh Forbes, Nathan Goff, Christopher S. Hansen, Matthias C. Hoffmann, D.M.P. Holland, Rebecca A. Ingle, Duan Luo, Sri Bhavya Muvva, Alexander H. Reid, Arnaud Rouzée, Artem Rudenko, Sajib Kumar Saha, Xiaozhe Shen, Anbu Selvam Venkatachalam, Xijie Wang, Matt R. Ware, Stephen Weathersby, Kyle Wilkin, Thomas Wolf, Yanwei Xiong, Jie Yang, Michael N. R. Ashfold, Daniel Rolles, Basile F. E. Curchod
Abstract
High Resolution Image Download MS PowerPoint Slide Identifying multiple rival reaction products and transient species formed during ultrafast photochemical reactions and determining their time-evolving relative populations are key steps toward understanding and predicting photochemical outcomes. Yet, most contemporary ultrafast studies struggle with clearly identifying and quantifying competing molecular structures/species among the emerging reaction products. Here, we show that mega-electronvolt ultrafast electron diffraction in combination with ab initio molecular dynamics calculations offer a powerful route to determining time-resolved populations of the various isomeric products formed after UV (266 nm) excitation of the five-membered heterocyclic molecule 2(5 H )-thiophenone. This strategy provides experimental validation of the predicted high (∼50%) yield of an episulfide isomer containing a strained three-membered ring within ∼1 ps of photoexcitation and highlights the rapidity of interconversion between the rival highly vibrationally excited photoproducts in their ground electronic state.