Chang, KristinaReduzzi, MaurizioWang, HanMarggi Poullaín, SoniaKobayashi, YukiBarreau, LouPrendergast, DavidNeumark, DanielLeone, Stephen2024-01-152024-01-152020Chang, K.F., Reduzzi, M., Wang, H. et al. Revealing electronic state-switching at conical intersections in alkyl iodides by ultrafast XUV transient absorption spectroscopy. Nat Commun 11, 4042 (2020). https://doi.org/10.1038/s41467-020-17745-w2041-172310.1038/s41467-020-17745-whttps://hdl.handle.net/20.500.14352/92995Conical intersections between electronic states often dictate the chemistry of photoexcited molecules. Recently developed sources of ultrashort extreme ultraviolet (XUV) pulses tuned to element-specific transitions in molecules allow for the unambiguous detection of electronic state-switching at a conical intersection. Here, the fragmentation of photoexcited iso-propyl iodide and tert-butyl iodide molecules (i-C3H7I and t-C4H9I) through a conical intersection between 3Q0/1Q1 spin–orbit states is revealed by ultrafast XUV transient absorption measuring iodine 4d core-to-valence transitions. The electronic state-sensitivity of the technique allows for a complete mapping of molecular dissociation from photoexcitation to photoproducts. In both molecules, the sub-100 fs transfer of a photoexcited wave packet from the 3Q0 state into the 1Q1 state at the conical intersection is captured. The results show how differences in the electronic state-switching of the wave packet in i-C3H7I and t-C4H9I directly lead to differences in the photoproduct branching ratio of the two systems.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal articlehttps://doi.org/10.1038/s41467-020-17745-wopen access544AbsorptionDetection methodElectronInorganic compoundMolecular analysisSpectroscopyQuímica física (Física)2206 Física Molecular2206.07-1 Espectroscopia láser