skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Kinetic Monte Carlo simulations of Pd deposition and island growth on MgO(100).

Abstract

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. The deposition and ripening of Pd atoms on the MgO(10 0) surface are modeled using kinetic Monte Carlo simulations. The density of Pd islands is obtained by simulating the deposition of 0.1 ML in 3 min. Two sets of kinetic parameters are tested and compared with experiment over a 200–800 K temperature range. One model is based upon parameters obtained by fitting rate equations to experimental data and assuming the Pd monomer is the only diffusing species. The other is based upon transition rates obtained from density functional theory calculations which show that small Pd clusters are also mobile. In both models, oxygen vacancy defects on the MgO surface provide strong traps for Pd monomers and serve as nucleation sites for islands. Kinetic Monte Carlo simulations show that both models reproduce the experimentally observed island density versus temperature, despite large differences in the energetics and different diffusion mechanisms. The low temperature Pd island formation at defects is attributed to fastmore » monomer diffusion to defects in the rate-equation-based model, whereas in the DFT-based model, small clusters form already on terraces and diffuse to defects. In the DFT-based model, the strong dimer and trimer binding energies at charged oxygen vacancy defects prevent island ripening below the experimentally observed onset temperature of 600 K.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1012315
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Surface Science, 601(14):3133-3142; Journal Volume: 601; Journal Issue: 14
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; PALLADIUM; DEPOSITION; SUBSTRATES; MAGNESIUM OXIDES; MONTE CARLO METHOD; KINETIC EQUATIONS; DENSITY FUNCTIONAL METHOD; BINDING ENERGY; VACANCIES; Environmental Molecular Sciences Laboratory

Citation Formats

Xu, Lijun, Campbell, Charles T., Jonsson, Hannes, and Henkelman, Graeme A. Kinetic Monte Carlo simulations of Pd deposition and island growth on MgO(100).. United States: N. p., 2007. Web. doi:10.1016/j.susc.2007.05.027.
Xu, Lijun, Campbell, Charles T., Jonsson, Hannes, & Henkelman, Graeme A. Kinetic Monte Carlo simulations of Pd deposition and island growth on MgO(100).. United States. doi:10.1016/j.susc.2007.05.027.
Xu, Lijun, Campbell, Charles T., Jonsson, Hannes, and Henkelman, Graeme A. Thu . "Kinetic Monte Carlo simulations of Pd deposition and island growth on MgO(100).". United States. doi:10.1016/j.susc.2007.05.027.
@article{osti_1012315,
title = {Kinetic Monte Carlo simulations of Pd deposition and island growth on MgO(100).},
author = {Xu, Lijun and Campbell, Charles T. and Jonsson, Hannes and Henkelman, Graeme A.},
abstractNote = {The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. The deposition and ripening of Pd atoms on the MgO(10 0) surface are modeled using kinetic Monte Carlo simulations. The density of Pd islands is obtained by simulating the deposition of 0.1 ML in 3 min. Two sets of kinetic parameters are tested and compared with experiment over a 200–800 K temperature range. One model is based upon parameters obtained by fitting rate equations to experimental data and assuming the Pd monomer is the only diffusing species. The other is based upon transition rates obtained from density functional theory calculations which show that small Pd clusters are also mobile. In both models, oxygen vacancy defects on the MgO surface provide strong traps for Pd monomers and serve as nucleation sites for islands. Kinetic Monte Carlo simulations show that both models reproduce the experimentally observed island density versus temperature, despite large differences in the energetics and different diffusion mechanisms. The low temperature Pd island formation at defects is attributed to fast monomer diffusion to defects in the rate-equation-based model, whereas in the DFT-based model, small clusters form already on terraces and diffuse to defects. In the DFT-based model, the strong dimer and trimer binding energies at charged oxygen vacancy defects prevent island ripening below the experimentally observed onset temperature of 600 K.},
doi = {10.1016/j.susc.2007.05.027},
journal = {Surface Science, 601(14):3133-3142},
number = 14,
volume = 601,
place = {United States},
year = {Thu May 24 00:00:00 EDT 2007},
month = {Thu May 24 00:00:00 EDT 2007}
}