Tungsten Cluster Migration on Nanoparticles: Minimum Energy Pathway and Migration Mechanism

Journal Article · Wed Mar 02 04:00:00 EST 2011 · The European Physical Journal. B., 80(1):31-40

DOI:https://doi.org/10.1140/epjb/e2011-10629-9· OSTI ID:1011782

Chen, Dong; Hu, Wangyu; Gao, Fei; Deng, Huiqiu; Sun, Lixian

Transition state searches have been employed to investigate the migration mechanisms of W clusters on W nanoparticles, and to determine the corresponding migration energies for the possible migration paths of these clusters. The tungsten clusters containing up to four adatoms are found to prefer 2D-compact structures with relatively low binding energies. The effect of interface and vertex regions on the migration behavior of the clusters is significantly strong, as compared to that of nanoparticle size. The migration mechanisms are quite different when the clusters are located at the center of the nanoparticle and near the interface or vertex areas. Near the interfaces and vertex areas, the substrate atoms tend to participate in the migration processes of the clusters, and can join the adatoms to form a larger cluster or lead to the dissociation of a cluster via the exchange mechanism, which results in the adatom crossing the facets. The lowest energy paths are used to be determined the energy barriers for W cluster migrations (from 1- to 4-atoms) on the facets, edges and vertex regions. The calculated energy barriers for the trimers suggest that the concerted migration is more probable than the successive jumping of a single adatom in the clusters. In addition, it of interest to note that the dimer shearing is a dominant migration mechanism for the tetramer, but needs to overcome a relatively higher migration energy than other clusters.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1011782
• Report Number(s): PNNL-SA-77850; 34899; KC0201020
• Journal Information: The European Physical Journal. B., 80(1):31-40, Journal Name: The European Physical Journal. B., 80(1):31-40 Journal Issue: 1 Vol. 80; ISSN 1434-6028
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOMS
Computer Simulation
DIMERS
DISSOCIATION
Defects
Environmental Molecular Sciences Laboratory
Nanoparticles: Migration of tungsten Cluster
SUBSTRATES
TUNGSTEN