TRACKING STRUCTURAL SOLVENT REORGANIZATION AND RECOMBINATION DYNAMICS FOLLOWING ELECTRON PHOTOABSTRACTION FROM AQUEOUS HALIDES WITH FEMTOSECOND X-RAY SPECTROSCOPY AND SCATTERING

Kubicek, Katharina

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https://hdl.handle.net/2142/122538 Copy

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Title

TRACKING STRUCTURAL SOLVENT REORGANIZATION AND RECOMBINATION DYNAMICS FOLLOWING ELECTRON PHOTOABSTRACTION FROM AQUEOUS HALIDES WITH FEMTOSECOND X-RAY SPECTROSCOPY AND SCATTERING

Author(s)

Kubicek, Katharina

Contributor(s)

• Bressler, Christian
• Herrmann, Carmen
• Thorwart, Michael
• Sekkal, Mohammed
• Nurekeyev, Zhangatay

Issue Date

2023-06-20

Keyword(s)

Mini-symposium: Spectroscopy at Large-scale Facilities

Abstract

We present a sub-picosecond resolved investigation of the structural solvent reorganization and geminate recombination dynamics of photogenerated halogen atoms in aqueous solutions. Nascent iodine radicals were generated via 400 nm 2-photon ionization of the parent iodide, while nascent bromine and chlorine atoms were generated via 1-photon ionization with 200 nm light. Time-resolved X-ray Absorption Near Edge Structure Spectroscopy around the L₁-edge of the photogenerated nascent iodine atoms (I⁰) delivered kinetic traces in agreement with a purely diffusion-driven geminate iodine-electron recombination model without the need of a long-lived (I⁰:e−) contact pair [1]. Nonequilibrium classical MD simulations indicate a delayed (ca. 100 fs) response of the caging H₂O solvent shell supported by the structural analysis of the X-ray Solution Scattering data. In-house QM/MM simulations [2] indicate a decreasing cage orientation time in the homologue series from Cl to I, which may be due to a more rigid H bond network around the smaller halogen atom. We will compare the femtosecond photodetachment results on iodide, measured at the LCLS X-ray Free Electron Laser (XFEL), with those on aqueous bromide ions, measured at SACLA XFEL, together with laser-only spectroscopy measurements on the nascent solvated electrons.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122538

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