High energy radiation femtochemistry of water molecules: early electron-radical pairs processes
| Autor: | Y. Glinec, Frédéric Burgy, Victor Malka, Jean-Philippe Rousseau, Yann Gauduel |
|---|---|
| Přispěvatelé: | Laboratoire d'optique appliquée (LOA), École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2010 |
| Předmět: |
chemistry.chemical_classification
Physics Electron pair Proton [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph] 02 engineering and technology 021001 nanoscience & nanotechnology Solvated electron 01 natural sciences Atomic and Molecular Physics and Optics chemistry 13. Climate action 0103 physical sciences Radiolysis Physics::Chemical Physics Atomic physics 010306 general physics 0210 nano-technology Ground state Inorganic compound Femtochemistry Energy (signal processing) |
| Zdroj: | The European Physical Journal D : Atomic, molecular, optical and plasma physics The European Physical Journal D : Atomic, molecular, optical and plasma physics, EDP Sciences, 2010, 60 (1), pp.121-135. ⟨10.1140/epjd/e2010-00152-2⟩ |
| ISSN: | 1434-6079 1434-6060 |
| DOI: | 10.1140/epjd/e2010-00152-2 |
| Popis: | The damages triggered by ionizing radiation on chemical and biological targets depend on the survival probability of radicals produced in clusters of ionization-excitation events. In this paper, we report on femtolysis (FEMTOsecond radioLYSIS) of pure liquid water using an innovative laser produced high-energy, ultra-short electron bunches in the 2.5-15 MeV range and high energy radiation femtochemistry (HERF) measurements. The short-time monitoring of a primary reducing radical, hydrated electron e $^{-}_{aq}$ , has been performed in confined ionization spaces (nascent spurs). The calculated yield of hydrated electrons at early time, $G({\rm e}^{-}_{aq})_{ET}$ , is estimated to be 6.5 ± 0.5 (number/100 eV) at t ~ 5 ps after the ultrafast energy deposition. This estimated value is high compare to (i) the available data of previous works that used scavenging techniques; (ii) the predictions of stochastic water radiolysis modelling for which the initial behaviour of hydrated electron is investigated in the framework of a classical diffusion regime of independent pairs. The HERF developments give new insights into the early ubiquitous radical escape probability in nascent aqueous spurs and emphasize the importance of short-lived solvent bridged electron-radical complexes [ ${\rm H}_{3}{\rm O}^{+...}$ ${\rm e}_{aq}^{-}$ .. ${\rm OH}]_{n{\rm H}_2{\rm O}}$ (non-independent pairs). A complete understanding of the G( ${\rm e}^{-}_{aq})_{ET}$ value needs to account for quantum aspects of 1s-like trapped electron ground state and neoformed prototropic radicals that govern ultra-fast recombination processes within these non-independent pair configurations. Femtolysis data emphasize that within a time-dependent non-diffusion regime, spatio-temporal correlations between hydrated electron and nearest neighbours OH radical or hydrated proton ( ${\rm H}_{3}{\rm O}^{+}$ ) would assist ultrafast anisotropic 1D recombination within solvent bridged electron-radical complexes. The emerging HERF domain would provide guidance for understanding of ultrashort-lived sub-structure of tracks and stimulate future semi-quantum simulations on prethermal radical reactions. |
| Databáze: | OpenAIRE |
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