  Motivated by recent experiments on colloidal systems with competing
attractive and repulsive interactions, we simulate a two-dimensional system of
colloids with competing interactions that can undergo fragmentation. In the
absence of any other confining potential, the colloids can form stable clusters
depending on the strength of the short range attractive term. By suddenly
changing the strength of one of the interaction terms we find a rich variety of
fragmentation behavior which is affected by the existence of "magic" cluster
numbers. Such soft matter systems can be used to construct artificial nuclei.
