<i>Ab Initio</i> Molecular Dynamics Simulation of Ethylene Reaction on Nickel (111) Surface

We performed <i>ab initio</i> molecular dynamics (MD) simulations of ethylene molecules on the nickel (111) surface to understand the initial stage of graphene growth via a chemical vapor deposition process. Several hydrogen atoms are dissociated from ethylene molecules during the MD simulations in three different reaction mechanisms. It is seen that the ethylene molecules are easily chemisorbed on the nickel surface. This chemisorption contributes significantly to the dissociation reactions of ethylene molecules on the nickel (111) surface. Furthermore, it is found from additional MD simulations that carbon atoms diffuse more easily into the nickel subsurface than carbon dimers

<i>Ab Initio</i> Molecular Dynamics Simulation of Ethylene Reaction on Nickel (111) Surface

We performed <i>ab initio</i> molecular dynamics (MD) simulations of ethylene molecules on the nickel (111) surface to understand the initial stage of graphene growth via a chemical vapor deposition process. Several hydrogen atoms are dissociated from ethylene molecules during the MD simulations in three different reaction mechanisms. It is seen that the ethylene molecules are easily chemisorbed on the nickel surface. This chemisorption contributes significantly to the dissociation reactions of ethylene molecules on the nickel (111) surface. Furthermore, it is found from additional MD simulations that carbon atoms diffuse more easily into the nickel subsurface than carbon dimers

Molecular Dynamics Simulation of Adhesion of Additive Molecules in Paint Materials toward Enhancement of Anticorrosion Performance

Adsorption energies of additive molecules in paint materials on the iron oxide substrate are investigated by molecular dynamics (MD) simulations to find the key feature of adhesion, which is one of the indispensable elements for the corrosion resistance of coated materials. Both edge-on and face-on adsorptions are observed for most additive molecules such as phenylsuccinic acid and benzoic acid. On the other hand, only the edge-on adsorption is observed for the specific molecule having a benzothiazole ring due to the effect of steric conformation. The largest adsorption energy per functional group is observed for two nitrogen atoms in the thiazole ring and amino group, which influences the relationship between face-on and edge-on adsorption energies. Moreover, a correlation analysis using RDKit descriptors is performed to discuss the dominant factor for the adsorption energy of additive molecules. The descriptor for the magnitude of partial charge relative to the molecular surface area and the one for the topological polar surface area have the largest correlation with the adsorption energy of the target molecules. It is significant in this study to extract key factors that contribute to molecular adhesion through MD simulations in combination with correlation analysis using RDKit descriptors. This study is a good example of the computer-assisted design of new paint materials

Proton Migration on Hydrated Surface of Cubic ZrO₂: <i>Ab initio</i> Molecular Dynamics Simulation

The proton migration on a cubic ZrO₂ (110) surface is investigated by <i>ab initio</i> molecular dynamics simulation. H₂O molecules form a hydrated multilayer on a ZrO₂ surface consisting of terminating H₂O adsorbates and hierarchically hydrogen-bonded H₂O layers. A portion of H₂O molecules chemisorbed on zirconium atoms (Zr–OH₂) dissociates into H⁺ and OH^–, forming polydentate and monodentate hydroxyls (>OH⁺ and Zr–OH^–). The coexistence of acid and base sites (Zr–OH₂ and Zr–OH^–) in the equilibrium state is confirmed by analyses of both forward and reverse reactions of H₂O dissociation on the ZrO₂ surface. Proton hopping from Zr–OH₂ to Zr–OH^– occurs by both a direct proton transfer and a chain protonation reaction via surrounding H₂O molecules. During these processes, Zr–OH₂ donates an extra proton to Zr–OH^– directly or via H₂O molecules in the multilayers, indicating that the coexistence of Zr–OH₂ and Zr–OH^– is a necessary condition for the proton conduction on the oxide surface with various basicities

Proton Migration on Hydrated Surface of Cubic ZrO₂: <i>Ab initio</i> Molecular Dynamics Simulation

The proton migration on a cubic ZrO₂ (110) surface is investigated by <i>ab initio</i> molecular dynamics simulation. H₂O molecules form a hydrated multilayer on a ZrO₂ surface consisting of terminating H₂O adsorbates and hierarchically hydrogen-bonded H₂O layers. A portion of H₂O molecules chemisorbed on zirconium atoms (Zr–OH₂) dissociates into H⁺ and OH^–, forming polydentate and monodentate hydroxyls (>OH⁺ and Zr–OH^–). The coexistence of acid and base sites (Zr–OH₂ and Zr–OH^–) in the equilibrium state is confirmed by analyses of both forward and reverse reactions of H₂O dissociation on the ZrO₂ surface. Proton hopping from Zr–OH₂ to Zr–OH^– occurs by both a direct proton transfer and a chain protonation reaction via surrounding H₂O molecules. During these processes, Zr–OH₂ donates an extra proton to Zr–OH^– directly or via H₂O molecules in the multilayers, indicating that the coexistence of Zr–OH₂ and Zr–OH^– is a necessary condition for the proton conduction on the oxide surface with various basicities

Catalyzed Growth of Carbon Nanotube with Definable Chirality by Hybrid Molecular Dynamics−Force Biased Monte Carlo Simulations

Metal-catalyzed growth mechanisms of carbon nanotubes (CNTs) were studied by hybrid molecular dynamics−Monte Carlo simulations using a recently developed ReaxFF reactive force field. Using this novel approach, including relaxation effects, a CNT with definable chirality is obtained, and a step-by-step atomistic description of the nucleation process is presented. Both root and tip growth mechanisms are observed. The importance of the relaxation of the network is highlighted by the observed healing of defects

Catalyzed Growth of Carbon Nanotube with Definable Chirality by Hybrid Molecular Dynamics−Force Biased Monte Carlo Simulations

Metal-catalyzed growth mechanisms of carbon nanotubes (CNTs) were studied by hybrid molecular dynamics−Monte Carlo simulations using a recently developed ReaxFF reactive force field. Using this novel approach, including relaxation effects, a CNT with definable chirality is obtained, and a step-by-step atomistic description of the nucleation process is presented. Both root and tip growth mechanisms are observed. The importance of the relaxation of the network is highlighted by the observed healing of defects