Thursday, 26 October 2006 - 8:30 AM
OLCC-McClain (Oakley-Lindsay Center)
40

Molecular dynamics: a study of density, potential energy, and atom plucking

Joseph D. Coppock and Brian G. Moore. Augustana College, Sioux Falls, SD

Molecular dynamics computer simulations were conducted on atomic clusters using constant energy and the Lennard-Jones 6-12 pair-wise potential, with emphasis on the liquid state. Large liquid clusters exist only at relatively high temperatures and have a large number of desorbing atoms, making the central cluster hard to identify and study. Multiple approaches to atom plucking were taken with a focus initially on potential energy plucking. Since most desorbed atoms have essentially zero potential energy, a potential energy cutoff is effective in plucking most desorbed atoms. However, larger clusters contained dimers and trimers which passed the initial potential energy plucking criterion; the existence of dimers was verified by visual analysis and neighbor statistics. An attempt was made to determine if a high but non-zero potential energy plucking criterion would ensure the plucking of all desorbed atoms and dimers without plucking atoms from the central cluster. A neighbor criterion plucking routine was also developed, to pluck dimers and trimers that passed potential energy criterion. Well plucked clusters were used to create two-dimensional histograms of potential energy (and other measures) versus radial distance for the core liquid cluster; this technique may eventually reveal new information about the structure of a cluster in the liquid state.


Web Page: savannah.nongnu.org/projects/clustersim/

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