Dissociative chemisorption of D2 on a Ni13 cluster (original) (raw)
Related papers
2000
The kinetics of the reactions of nickel clusters with a deuterium molecule are studied. Dissociative chemisorption probabilities of the D 2 molecule on the small Ni n (n=7-10) clusters are computed by a quasi-classical molecular dynamics computer simulation technique. Structures of the clusters are obtained by an embedded-atom potential, and the interaction between the D 2 and Ni n is modelled by an LEPS (London-Eyring-Polanyi-Sato) function (energy surface). This analysis includes the chemisorption probabilities as functions of the impact parameter and of the relative translational energy of the D 2. The corresponding reactive cross-sections for the ground state of the molecule are calculated as functions of the collision energy and the size of the cluster. The role of the size of the clusters is examined. An indirect mechanism to the reaction, which involves formation of molecular adsorption as precursors to dissociative adsorption in the low collision energy region (less than 0.1 eV), is observed. Results are discussed by comparing with the other similar theoretical and experimental studies.
Reactions of small Ni clusters with a diatomic molecule: MD simulation of D2+Nin (n=7–10) systems
Surface Science, 2000
The kinetics of the reactions of nickel clusters with a deuterium molecule are studied. Dissociative chemisorption probabilities of the D 2 molecule on the small Ni n (n=7-10) clusters are computed by a quasi-classical molecular dynamics computer simulation technique. Structures of the clusters are obtained by an embedded-atom potential, and the interaction between the D 2 and Ni n is modelled by an LEPS (London-Eyring-Polanyi-Sato) function (energy surface). This analysis includes the chemisorption probabilities as functions of the impact parameter and of the relative translational energy of the D 2 . The corresponding reactive cross-sections for the ground state of the molecule are calculated as functions of the collision energy and the size of the cluster. The role of the size of the clusters is examined. An indirect mechanism to the reaction, which involves formation of molecular adsorption as precursors to dissociative adsorption in the low collision energy region ( less than 0.1 eV ), is observed. Results are discussed by comparing with the other similar theoretical and experimental studies.
Surface Science, 2004
D 2 + Ni-surface collision system has been studied by a quasiclassical molecular dynamic simulation method. Dissociative adsorption of a D 2 molecule on rigid Ni(1 0 0), Ni(1 1 0) and Ni(1 1 1) surfaces are investigated. Interactions between the molecule and Ni surfaces were described by a LEPS potential. The contour plots of the LEPS function is presented as functions of the distances between the center of mass of the D 2 and surface, and between the two deuterium atoms (D-D) for topologically different sites of the surfaces. Dissociative chemisorption probabilities of the D 2 (v ¼ 0, j ¼ 0) molecule on various sites of the surfaces are presented for different translation energies between 0.001 and 1.0 eV. The probabilities obtained at each collision site have unique behavior. At low collision energies indirect processes enhance the reactivity. The results are compared with the available studies. The physical mechanisms underlying the results are discussed.
Molecule-cluster collisions: reaction of D 2 with Ni 14
Ari an International Journal For Physical and Engineering Sciences, 1998
The reactive channel (dissociative of the molecule on the cluster) of the D # Ni collision system is studied via quasi-classical molecular dynamics (MD) computer simulations. This is analysed as functions of the initial rovibrational molecular state and collision energy. The Ni cluster is at room temperature. The geometry of the cluster is obtained by embedded-atom (EA) model potential, and the interaction between D and Ni is modelled by LEPS (Landon-Eyring-Polanyi-Sato) potential surface.
Brazilian Journal of Physics, 2006
A quasiclassical and micro-canonical molecular dynamic simulation techniques have been applied for D 2 (v, j) + Ni-surface collision systems. Dissociative adsorptions of a D 2 molecule on the rigid low index (100), (110) and (111), surfaces of the nickel are investigated to understand the effects of the different surfaces, impact sites and the initial rovibrational states of the molecule on molecule-surface collisions. Interactions between the molecule and the Ni surfaces are mimicked by a LEPS potential. Dissociative chemisorption probabilities of the D 2 (v, j) Molecule ( for the vibrational (v) = 0 and rotational ( j) = 0, 1, 3, 10, and for the v = 1, j = 0 states on different impact sites of the surfaces) are presented for the translation energies between 0.001 and 1.0 eV . The probabilities obtained at each collision site have unique behavior for the colliding molecule which is moving along the surface normal direction. It has been observed that at the low collision energies the indirect processes (steering effects) enhance the reactivity on the surfaces. The results are compared to the related studies in the literature.
Reactivity of the Nin(T) (n=54,55,56) clusters with D2(v,j) molecule: molecular dynamics simulations
Surface Science, 2004
The reactive channel of the D 2 ðv; jÞ þ Ni n ðT Þ (n ¼ 54; 55; 56) collision system is studied via quasiclassical molecular dynamics simulations. The cluster is described using an embedded-atom potential, and the interaction between the molecule and the cluster is modeled by a LEPS (London-Eyring-Polanyi-Sato) potential energy function. Dissociative chemisorption probabilities are computed as functions of the impact parameter and the collision energy, and are used to evaluate the reaction cross-sections. Effects of the initial rovibrational states of the molecule and the temperatures of the clusters on the reactive channel are analyzed. Reaction rate constants are also computed and compared with those measured experimentally.
DFT study of 2-butyne-1,4-diol adsorption on Ni(111) or Ni(100) clusters
Applied Surface Science, 2012
Density functional theory (DFT) calculation was applied to acetylene (AC) and 2-butyne-1,4-diol (BD) adsorbed on an Ni(1 1 1) or Ni(1 0 0) model cluster surface in order to elucidate the relationship between their electronic states and geometry in the adsorption process. Adsorption energy of AC calculated using BSSE correction and binding structure were in good agreement with the experimental data. The geometry and adsorption energy of AC or BD on the Ni(1 1 1) surface in the optimized adsorption condition differ from those on the Ni(1 0 0) surface. Analysis of a natural electron configuration of adsorbates before and after adsorption on Ni clusters clarified that the 2s orbital rather than other orbitals such as 2p contributed mainly to the adsorption energy.
Journal of Molecular Modeling, 2011
Hydrogen dissociative chemisorption and desorption on small lowest energy Ni n clusters up to n=13 as a function of H coverage was studied using density functional theory. H adsorption on the clusters was found to be preferentially at edge sites followed by 3-fold hollow sites and on-top sites. The minimum energy path calculations suggest that H 2 dissociative chemisorption is both thermodynamically and kinetically favorable and the H atoms on the clusters are mobile. Calculations on the sequential H 2 dissociative chemisorption on the clusters indicate that the edge sites are populated first and subsequently several on-top sites and hollow sites are also occupied upon full cluster saturation. In all cases, the average hydrogen capacity on Ni n clusters is similar to that of Pd n clusters but considerably smaller than that of Pt n clusters. Comparison of hydrogen dissociative chemisorption energies and H desorption energies at full H-coverage among the Ni family clusters was made.
Dynamics of the D2 + Ni(100) collision system: Analysis of the reactive and inelastic channels
International Journal of Quantum Chemistry, 2001
The reactive and scattering channels of the D2(v,j)+Ni(100) collision system are studied using quasiclassical molecular dynamics simulations. The interaction between the D2 and the atoms of the surface is modeled by a LEPS (London–Eyring–Polani–Sato) potential energy function. The molecule is aimed at three different impact sites (atop, bridge, and center) of a rigid Ni(100) surface along the normal direction with various collision energies ≤1.0 eV. Dissociative chemisorption probabilities are computed for different rotational states of the molecule. Probability distributions of the final rovibrational states of the ground‐state D2 molecule scattered from those impact sites are also computed as a function of the collision energy. Higher collision energy results in excitation of higher rotational and/or vibrational states of the scattered molecule. At collision energies below 0.1 eV an indirect dissociation mechanism (through molecular adsorption) dominates the reaction. © 2001 John ...
The Journal of Chemical Physics, 2006
The results of theoretical calculations of associative desorption of CH 4 and H 2 from the Ni͑111͒ surface are presented. Both minimum-energy paths and classical dynamics trajectories were generated using density-functional theory to estimate the energy and atomic forces. In particular, the recombination of a subsurface H atom with adsorbed CH 3 ͑methyl͒ or H at the surface was studied. The calculations do not show any evidence for enhanced CH 4 formation as the H atom emerges from the subsurface site. In fact, there is no minimum-energy path for such a concerted process on the energy surface. Dynamical trajectories started at the transition state for the H-atom hop from subsurface to surface site also did not lead to direct formation of a methane molecule but rather led to the formation of a thermally excited H atom and CH 3 group bound to the surface. The formation ͑as well as rupture͒ of the H-H and C-H bonds only occurs on the exposed side of a surface Ni atom. The transition states are quite similar for the two molecules, except that in the case of the C-H bond, the underlying Ni atom rises out of the surface plane by 0.25 Å. Classical dynamics trajectories started at the transition state for desorption of CH 4 show that 15% of the barrier energy, 0.8 eV, is taken up by Ni atom vibrations, while about 60% goes into translation and 20% into vibration of a desorbing CH 4 molecule. The most important vibrational modes, accounting for 90% of the vibrational energy, are the four high-frequency CH 4 stretches. By time reversibility of the classical trajectories, this means that translational energy is most effective for dissociative adsorption at low-energy characteristic of thermal excitations but energy in stretching modes is also important. Quantum-mechanical tunneling in CH 4 dissociative adsorption and associative desorption is estimated to be important below 200 K and is, therefore, not expected to play an important role under typical conditions. An unexpected mechanism for the rotation of the adsorbed methyl group was discovered and illustrated a strong three-center C-H-Ni contribution to the methyl-surface bonding.