投稿者: 博佐藤

Journal of Computer Chemistry, Japan [No.2015-0016] Published online in advanced by J-STAGE
<Title:> Molecular Dynamics Simulation of the Behavior of Beryllium Diffusion in Corundum
<Author(s):> Jun Kawano, Muneyuki Okuyama, Takeshi Miyata<Abstract:> Molecular dynamics (MD) simulations are highly useful for analyzing atomic behavior during diffusion, especially in systems that are difficult to investigate experimentally. The focus of the present study was the diffusion behavior of Be in corundum, which was analyzed by MD calculations. First, we derived new potential parameter sets for O, Al, and Be. This parameter set was verified to well reproduce the structures and properties of corundum, bromellite, and chrysoberyl. Based on MD simulations of corundum containing Be as interstitial atoms, where the simulations were performed using the newly derived potential parameters, the diffusion coefficient was estimated to be approximately 10-7 cm2/s at around 2100 K. This is consistent with previously published experimental results, which confirms the validity of the MD simulation. The present calculations also reveal the detailed atomic movement, where Be atoms jump between Al sites and/or interstitial sites, and that the activation energy of this process is approximately 1.1 × 102 kJ/mol.
<Keywords:> Diffusion, Molecular dynamics simulation, Corundum, Beryllium, Gemology
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URL: https://www.jstage.jst.go.jp/article/jccj/advpub/0/advpub_2015-0016/_article/-char/ja/
Corresponding author E-Mill: j-kawano(at)mail.sci.hokudai.ac.jp

Journal of Computer Chemistry, Japan [No.2015-0008] Published online in advanced by J-STAGE
Title: Interlayer Bonding Energy of Mg-Chlorite: A Density Functional Theory Study
Author(s): Hiroshi SakumaAbstract: Interlayer bonding energy (ILBE) of Mg-chlorite was calculated based on the density functional theory with dispersion force correction (DFT-D2). The calculated ILBE of Mg-chlorite was smaller than brucite, phlogopite, gibbsite, and muscovite and was comparable to talc, kaolinite, pyrophyllite, and lizardite. The attractive interaction between layers would be generated by the weak hydrogen bond between layers. The ILBE of Mg-chlorite should be the minimum ILBE in natural chlorite group, since the natural chlorite shows the isomorphic substitution which induces high layer charge resulting in stronger attractive interaction between layers like phlogopite and muscovite.
Keywords: Separation energy, Friction, Clay mineral, Chlorite, DFT
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URL: https://www.jstage.jst.go.jp/article/jccj/advpub/0/advpub_2015-0008/_article/-char/ja/
Corresponding author E-Mill: SAKUMA.Hiroshi(at)nims.go.jp