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Series

1990

Iowa State University

Biological and Chemical Physics

Articles 1 - 3 of 3

Full-Text Articles in Physics

Low-Temperature Epitaxial Growth Of Thin Metal Films, James W. Evans, D. E. Sanders, Patricia A. Thiel, Andrew E. Depristo Mar 1990

Low-Temperature Epitaxial Growth Of Thin Metal Films, James W. Evans, D. E. Sanders, Patricia A. Thiel, Andrew E. Depristo

Chemistry Publications

We present a different mechanism to explain the occurrence of long-lived oscillations in diffraction spot intensities during epitaxial growth of metal films on fcc (100) substrates at low temperature. Rather than rely on the common picture of cyclical nucleation and growth to produce the oscillations, the model invokes ‘‘downward funneling’’ deposition dynamics to fourfold-hollow adsorption sites.


Cluster Diffusivity: Structure, Correlation, And Scaling, H. C. Kang, P. A. Thiel, James W. Evans Jan 1990

Cluster Diffusivity: Structure, Correlation, And Scaling, H. C. Kang, P. A. Thiel, James W. Evans

Physics and Astronomy Publications

We have investigated the diffusion of clusters on a triangular lattice using Monte Carlo simulations. A cluster is defined as a two‐dimensional collection of particles which are connected to each other, either directly or indirectly through other particles in the cluster, by nearest‐neighbor bonds. Each particle is allowed to hop, with probability αδb/2/(α−δb/2+αδb/2), to a vacant nearest‐neighbor site with the constraint that the hop does not break the cluster. The change in the number of bonds is given by δb. The equilibrium clusters are correlated animals with ...


Inequivalent Models Of Irreversible Dimer Filling: ‘‘Transition State’’ Dependence, R. S. Nord, James W. Evans Jan 1990

Inequivalent Models Of Irreversible Dimer Filling: ‘‘Transition State’’ Dependence, R. S. Nord, James W. Evans

Physics and Astronomy Publications

Irreversible adsorption of diatomics on crystalline surfaces is sometimes modeled as random dimer filling of adjacent pairs of sites on a lattice. We note that this process can be implemented in two distinct ways: (i) randomly pick adjacent pairs of sites,  jj’, and fill  jj’ only if both are empty (horizontal transition state); or (ii) randomly pick a single site,  j, and if  j and at least one neighbor are empty, then fill  j and a randomly chosen empty neighbor (vertical transition state). Here it is instructive to consider processes which also include competitive random monomer filling of ...