Time-dependent yield of the hydrated electron and the hydroxyl radical in D$_2$O: a picosecond pulse radiolysis study
| Autor: | Furong Wang, Uli Schmidhammer, Jean-Louis Marignier, Zizhao Zong, Mehran Mostafavi, J.-P. Larbre |
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| Přispěvatelé: | Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Isosbestic point
[PHYS]Physics [physics] Materials science Absorption spectroscopy 010308 nuclear & particles physics Analytical chemistry General Physics and Astronomy 02 engineering and technology Molar absorptivity 021001 nanoscience & nanotechnology Solvated electron 01 natural sciences chemistry.chemical_compound chemistry Yield (chemistry) 0103 physical sciences Ultrafast laser spectroscopy Radiolysis Hydroxyl radical Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Phys.Chem.Chem.Phys. Phys.Chem.Chem.Phys., 2018, 20 (23), pp.15671-15679. ⟨10.1039/c8cp02276c⟩ |
| Popis: | International audience; Picosecond pulse radiolysis measurements were performed in neat D2O and H2O in order to study the isotopic effect on the time-resolved yield of the hydrated electron and hydroxyl radical. First, the absorption band of the hydrated electron in D2O, e(D2O)(-), is measured between 250 and 1500 nm. The molar absorption coefficient of the solvated electron spectrum in D2O was determined using the isosbestic point method by scavenging the solvated electron using methyl viologen. The amplitude and shape of the absorption spectrum of the hydrated electron in D2O are different from those previously reported in the literature. The maximum of the hydrated electron in the D2O absorption band is ca. 704 nm with a molar absorption coefficient of (22 900 +/- 500) L mol(-1) cm(-1). Based on this extinction coefficient, the radiolytic yield of e(D2O)(-) just after the 7 ps electron pulse was determined to be (4.4 +/- 0.2) x 10(-7) mol J(-1), which coincides with the one for e(H2O)(-) in H2O. The time-dependent radiolytic yield of e(D2O)(-) was determined from a few ps to 8 ns. To determine the OD center dot radical yield, the contribution of the solvated electron and of the transient species produced by the electron pulse in the windows of the fused silica optical cell was taken into account for the analysis of the transient absorption measurements at 260 nm. Therefore, an appropriate experimental methodology is used for measuring low absorbance at two different wavelengths in ps pulse radiolysis. The yield of the OD center dot radical just after the 7 ps electron pulse was found to be (5.0 +/- 0.2) x 10(-7) mol J(-1). In the spurs of ionization, the decay rate of e(D2O)(-) is slower than e(H2O)(-), whereas the decay rate of OD center dot is similar to the one of OH center dot. Here, the established time-dependent yield of the solvated electron and the hydroxyl radical provide the foundation for improving the models used for spur reaction simulations in heavy water mainly for the chemistry of CANDU reactors. |
| Databáze: | OpenAIRE |
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