#
Information on Physics in CSC

## Background on Buckyballs

The recently discovered carbon fullerenes, such as the C_{60}
"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 C_{60}-C_{240} Collisions
and C_{60} Melting

In movies showing
C_{60}-C_{240} collisions
and
C_{60} 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
C_{240} cluster upon impact of the smaller C_{60} cluster. In
the movie on C_{60} melting, color is used to visualize the binding
energy of atoms.

This page has been visited
times since March 9, 1997

CSC Pages by:
Charles Henrich and
David Tomanek
at Michigan State University

Contact: tomanek@pa.msu.edu /
Last update: 4 February 1997