Information on Physics in CSC

Background on Buckyballs

The recently discovered carbon fullerenes, such as the C60 "buckyball" , are stable molecules with exciting properties. When condensed to a solid, this form of carbon is very different from graphite or diamond. Topologically, the hollow fullerene structures (similar to the CSC logo) can be obtained by rolling a piece of a graphite layer onto itself, thereby cutting few interatomic bonds. In reality, the formation process is much more complex, involving aggregation from gas phase, as well as interatomic and cluster-cluster collisions.

O(N) Molecular Dynamics Code

We model the dynamics of cluster-cluster collisions using molecular dynamics simulations. Our code is portable from a single-processor scalar machine to massively parallel computers, thanks to a formalism which allows to calculate the quantum mechanical forces acting on individual atoms "locally", without the detailed knowledge of the entire system. This formalism is decribed in the paper Total Energy Calculations for Extremely Large Clusters: The Recursive Approach. In this formalism, the total CPU time per time step is proportional to the number of atoms.

Simulations of C60-C240 Collisions and C60 Melting

In movies showing C60-C240 collisions and C60 melting we visualize the detailed dynamics of these processes using time steps of 5x10-16 seconds. In the collision movie, color is used to visualize the temperature, given by the kinetic energy of individual atoms. Note that a heat wave accompanies the shock wave propagating through the larger C240 cluster upon impact of the smaller C60 cluster. In the movie on C60 melting, color is used to visualize the binding energy of atoms.

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CSC Pages by: Charles Henrich and David Tomanek at Michigan State University
Contact: / Last update: 4 February 1997