  The dynamics of rapidly collapsing bubbles are of great interest due to the
high degree of energy focusing that occurs withing the bubble. Molecular
dynamics provides a way to model the interior of the bubble and couple the gas
dynamics with the equations governing the bubble wall. While much theoretical
work has been done to understand how a bubble will respond to an external
force, the internal dynamics of the gas system are usually simplified greatly
in such treatments. This paper shows how the gas system dynamics affect bubble
collapse and illustrates what effects various modeling assumptions can have on
the motion of the bubble wall. In addition, we present a method of adaptively
partitioning space to improve the performance of collision intersection
calculations when using an energy dependent collision cross section.
