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Kinetic Monte Carlo simulation of hydrogen diffusion on tungsten reconstructed (0 0 1) surface |
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| Affiliation: | 1. Laboratory of Plasma Physics and Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628, Japan;2. Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan;1. SCK·CEN, Nuclear Materials Science Institute, Boeretang 200, Mol, 2400, Belgium;2. Ghent University, Applied Physics EA17 FUSION-DC, St.Pietersnieuwstraat, 41 B4, B-9000, Gent, Belgium;3. Department of Experimental Nuclear Physics K-89, Institute of Physics, Nanotechnologies, and Telecommunications, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russia;4. Max-Planck-Institut für Plasmaphysik, Garching, Germany;1. University of California, San Diego, La Jolla, CA 92093, USA;2. Los Alamos National Laboratory, Los Alamos, NM 8754, USA;3. Nuclear Research National University MEPhI, Moscow 115409, Russia;1. School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China;2. Gansu Analysis and Research Center, Lanzhou 730000, China |
| Abstract: | A kinetic Monte Carlo (KMC) algorithm has been developed to study the hydrogen diffusion on tungsten reconstructed (0 0 1) surface in the temperature range 220–300 K. The hydrogen diffusion coefficients predicted by the developed KMC code match the experimental values very well at low hydrogen coverage of a fraction of monolayer. A diffusion coefficient formula as a function of temperature and hydrogen coverage was derived from KMC simulations. Due to the very low probability of hydrogen occupying the long bridge adsorption sites, the rates of hydrogen atom having 3 or 4 neighbors are found to be zero for hydrogen coverage much less than a monolayer, while the rates of hydrogen atom having 0–2 neighbors are linear with respect to the hydrogen coverage. The calculated average rates of hydrogen located at the LB sites are very close to zero for low hydrogen coverage. Hydrogen only starts to occupy the LB sites after almost all SB sites are occupied. |
| Keywords: | Kinetic Monte Carlo Diffusion coefficient Hydrogen diffusion Tungsten reconstructed surface |
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