The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Chrystèle Sanloup - One of the best experts on this subject based on the ideXlab platform.
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Noble Gas Reactivity in Planetary Interiors
Frontiers in Physics, 2020Co-Authors: Chrystèle SanloupAbstract:While the field of Noble Gas reactivity essentially belongs to chemistry, Earth and planetary sciences have brought a different perspective to the field. Indeed, planetary interiors are natural high pressure (P) and high temperature (T) laboratories, where conditions exist where bonding of the heaviest Noble Gases may be induced thermodynamically through volume reduction (Le Châtelier's principle). Earth and planetary sciences besides generate numerous and precise observations such as the depletion of the terrestrial and martian atmospheres in xenon, pointing to the potential for Xe to be sequestered at depth, potentially induced by its reactivity. More generally, this paper will review the advances on Noble Gas reactivity at the extreme P-T conditions found within planetary interiors from experiments and theoretical investigations. This review will cover the synthesis of cage compounds, stoichiometric oxides and metals, and non-stoichiometric compounds where Noble Gases are only minor or trace elements but could be essential in solving some Earth and planetary puzzles. An apparent trend in Noble Gas reactivity with P emerges. In the case of Xe which is the most documented, metals are synthesized above 150 GPa, i.e., at terrestrial core conditions, stoichiometric Xe-oxides between 50 and 100 GPa, i.e., in the P-T range of the Earth's lower mantle, but Xe-O high energy bonds may also form under the modest pressures of the Earth's crust (
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Noble Gas Reactivity in Planetary Interiors
Frontiers in Physics, 2020Co-Authors: Chrystèle SanloupAbstract:While the field of Noble Gas reactivity essentially belongs to chemistry, Earth and planetary sciences have brought a different perspective to the field. Indeed, planetary interiors are natural high pressure (P) and high temperature (T) laboratories, where conditions exist where bonding of the heaviest Noble Gases may be induced thermodynamically through volume reduction (Le Châtelier’s principle). Earth and planetary sciences besides generate numerous and precise observations such as the depletion of the terrestrial and martian atmospheres in xenon, pointing to the potential for Xe to be sequestered at depth, potentially induced by its reactivity. More generally, this paper will review the advances on Noble Gas reactivity at the extreme P-T conditions found within planetary interiors from experiments and theoretical investigations. This review will cover the synthesis of cage compounds, stoichiometric oxides and metals, and non-stoichiometric compounds where Noble Gases are only minor or trace elements but could be essential in solving some Earth and planetary puzzles. An apparent trend in Noble Gases reactivity with P emerges. In the case of Xe which is the most documented, metals are synthesized above 150 GPa, i.e. at terrestrial core conditions, stoichiometric Xe-oxides between 50 GPa and 100 GPa, i.e. in the P -T range of the Earth’s lower mantle, but Xe-O high energy bonds may also form under the modest pressures of the Earth’s crust (less than 1 GPa) in non-stoichiometric compounds. Most planetary relevant Noble Gas compounds found are with xenon, with only a few predicted helium compounds, the latter having no or very little charge transfer between helium and neighbouring atoms.
Ping Huai - One of the best experts on this subject based on the ideXlab platform.
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first principles study of helium behavior in nickel with Noble Gas incorporation
Journal of Applied Physics, 2020Co-Authors: Liangxiang Liao, Xun Zhang, Cuilan Ren, Zhengde Zhang, Hefei Huang, Ping HuaiAbstract:The behavior of helium in nickel with Noble Gas atom (helium, neon, argon, krypton, and xenon) incorporations is systematically studied by using the first-principles method. The formation energies of Noble Gas atoms in nickel increase with atomic size increase from helium to xenon. All Noble Gas atoms considered in this work energetically prefer to stay at the substitutional sites when compared to the interstitial ones. The variations in formation energies among Noble Gas atoms can be mainly attributed to the steric effects caused by their incorporation. The chemical binding between nickel and Noble Gas atoms are further identified by their projected density of states. The substitutional Noble Gas shows a trapping effect on interstitial helium, and their binding energies also exhibit an approximately linear relation with their size. In addition, the effect of Noble Gas incorporation on helium clustering in nickel is studied. It shows that Noble Gas atoms attract small helium clusters and further repel the relatively larger ones. The results help to understand the influence of Noble Gas atoms on the fundamental helium behavior such as helium stability, trapping, and clustering in nickel and are also technologically important for further study on helium bubble nucleation under similar irradiation conditions.
Walter Kutschera - One of the best experts on this subject based on the ideXlab platform.
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tracing Noble Gas radionuclides in the environment
Annual Review of Nuclear and Particle Science, 2004Co-Authors: P Collon, Walter KutscheraAbstract:▪ Abstract Trace analysis of radionuclides is an essential and versatile tool in modern science and technology. Because of their ideal geophysical and geochemical properties, long-lived Noble Gas radionuclides—particularly 39Ar (t1/2 = 269 y), 81Kr (t1/2 = 2.3 × 105 y), and 85Kr (t1/2 = 10.8 y)—have long been recognized to have a wide range of important applications in Earth sciences. In recent years, significant progress in the development of practical analytical methods has led to applications of these isotopes in the hydrosphere (tracing the flow of groundwater and ocean water). In this article, we introduce the applications of these isotopes and review three leading analytical methods: low-level counting (LLC), accelerator mass spectrometry (AMS) and atom trap trace analysis (ATTA).
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tracing Noble Gas radionuclides in the environment
arXiv: Nuclear Experiment, 2004Co-Authors: P Collon, Walter KutscheraAbstract:Trace analysis of radionuclides is an essential and versatile tool in modern science and technology. Due to their ideal geophysical and geochemical properties, long-lived Noble Gas radionuclides, in particular, 39Ar (t1/2 = 269 yr), 81Kr (t1/2 = 2.3x10^5 yr) and 85Kr (t1/2 = 10.8 yr), have long been recognized to have a wide range of important applications in Earth sciences. In recent years, significant progress has been made in the development of practical analytical methods, and has led to applications of these isotopes in the hydrosphere (tracing the flow of groundwater and ocean water). In this article, we introduce the applications of these isotopes and review three leading analytical methods: Low-Level Counting (LLC), Accelerator Mass Spectrometry (AMS) and Atom Trap Trace Analysis (ATTA).
William Happer - One of the best experts on this subject based on the ideXlab platform.
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Spin-exchange optical pumping of Noble-Gas nuclei
Reviews of Modern Physics, 1997Co-Authors: Thad Walker, William HapperAbstract:Spin-exchange optical pumping of mixtures of alkali-metal vapors and Noble Gases can be used to efficiently polarize the nuclei of the Noble-Gas atoms. Liters of Noble Gases at standard temperature and pressure and with nuclear spin polarizations of several tens of percent are now used in many applications. The authors describe the basic phenomena that govern the spin-exchange process and review the physics of angular momentum transfer and loss in optical pumping and spin-exchange collisions. {copyright} {ital 1997} {ital The American Physical Society}
Liangxiang Liao - One of the best experts on this subject based on the ideXlab platform.
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first principles study of helium behavior in nickel with Noble Gas incorporation
Journal of Applied Physics, 2020Co-Authors: Liangxiang Liao, Xun Zhang, Cuilan Ren, Zhengde Zhang, Hefei Huang, Ping HuaiAbstract:The behavior of helium in nickel with Noble Gas atom (helium, neon, argon, krypton, and xenon) incorporations is systematically studied by using the first-principles method. The formation energies of Noble Gas atoms in nickel increase with atomic size increase from helium to xenon. All Noble Gas atoms considered in this work energetically prefer to stay at the substitutional sites when compared to the interstitial ones. The variations in formation energies among Noble Gas atoms can be mainly attributed to the steric effects caused by their incorporation. The chemical binding between nickel and Noble Gas atoms are further identified by their projected density of states. The substitutional Noble Gas shows a trapping effect on interstitial helium, and their binding energies also exhibit an approximately linear relation with their size. In addition, the effect of Noble Gas incorporation on helium clustering in nickel is studied. It shows that Noble Gas atoms attract small helium clusters and further repel the relatively larger ones. The results help to understand the influence of Noble Gas atoms on the fundamental helium behavior such as helium stability, trapping, and clustering in nickel and are also technologically important for further study on helium bubble nucleation under similar irradiation conditions.
