超純水のみによる電気化学的加工法の研究 : 陰極Al(001)表面における除去加工現象の第一原理分子動力学シミュレーション

概要

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In order to reveal the mechanism of the electrochemical processes of cathode surfaces in ultrapure water, first-principles molecular-dynamics simulations of chemical reaction on the Al (001) surfaces interacting with H atoms, H_2O molecules and OH molecule were carried out on the basis of the Kohn-Sham local-density-functional formalism. A plane-wave basis set was used, and the cut-off energy is 594eV (64Ry). A norm-conserving pseudopotential was also used. We adopt the standard molecular-dynamics method for the optimization of the ionic system and the preconditioned conjugate-gradient (CG) method for the quenching procedure of the electronic degrees of freedom. We determined the optimized atomic configurations and electronic distributions for H atom and H_2O or OH molecule chemisorbed Al (001) surfaces. It was confirmed that an H atom reacts with H_2O molecules on the Al (001) surface to produce an OH molecule. Chemisorption of an OH molecules and H atoms to the Al (001) surface atom breaks the back-bonds and side-bonds, and the Al (001) surface atom is etched as an AlH_2OH molecule. From these simulated results, we concluded that the electrochemical etching of Al (001) cathode surface in ultrapure water is induced by H atoms and OH molecules.
社団法人精密工学会の論文
2003-09-05