Hypothesis about electron quantum tunneling during sonochemical splitting of water molecule
| Autor: | R. Pflieger, Sergey I. Nikitenko, Timothé Di Pasquale, Tony Chave |
|---|---|
| Přispěvatelé: | Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Acoustics and Ultrasonics
Hydrogen chemistry.chemical_element 02 engineering and technology Electron 010402 general chemistry 01 natural sciences 7. Clean energy water splitting Dissociation (chemistry) Sonochemistry Inorganic Chemistry Sonoluminescence kinetic isotope effect Kinetic isotope effect Chemical Engineering (miscellaneous) Environmental Chemistry Radiology Nuclear Medicine and imaging Quantum tunnelling plasma Organic Chemistry 021001 nanoscience & nanotechnology 0104 chemical sciences [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry chemistry Chemical physics 0210 nano-technology sonochemistry quantum tunneling Self-ionization of water |
| Zdroj: | Ultrasonics Sonochemistry Ultrasonics Sonochemistry, Elsevier, 2020, 60, pp.104789. ⟨10.1016/j.ultsonch.2019.104789⟩ Ultrasonics Sonochemistry, 2020, 60, pp.104789. ⟨10.1016/j.ultsonch.2019.104789⟩ |
| ISSN: | 1350-4177 |
| DOI: | 10.1016/j.ultsonch.2019.104789⟩ |
| Popis: | International audience; Quantum tunneling in chemistry is often attributed to the processes at low or near room temperatures when the rate of thermal reactions becomes far less than the rate of quantum tunneling. However, in some rapid processes, quantum tunneling can be observed even at high temperatures. Herein, we report the experimental evidence for anomalous H/D kinetic isotope effect (KIE) during sonochemical dissociation of water molecule driven by 20 kHz power ultrasound measured in H 2 O/D 2 O mixtures saturated with Ar or Xe. Hydrogen released during ultrasonic treatment is enriched by light isotope. The observed H/D KIE (α=2.15-1.50) is much larger than what is calculated assuming a classical KIE for T g =5000 K (α=1.15) obtained from the sonoluminescence spectra in H 2 O and D 2 O. Furthermore, the α values sharply decrease with increasing of H 2 O content in H 2 O/D 2 O mixtures reaching a steady-state value close to α=1.50, which also cannot be explained by O-H/O-D zero-point energy difference. We suggest that these results can be understood in terms of quantum electron tunneling occurring in nonequilibrium picosecond plasma produced at the last stage of cavitation bubble collapse. Thermal homolytic splitting of water molecule is inhibited by extremely short lifetime of such plasma. On the contrary, immensely short traversal time for electron tunneling in water allows H 2 O dissociation by quantum tunneling mechanism. |
| Databáze: | OpenAIRE |
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