  We prove that time-periodic solutions arise via Hopf bifurcation in a finite
closed system of coagulation-fragmentation equations. The system we treat is a
variant of the Becker-Doering equations, in which clusters grow or shrink by
addition or deletion of monomers. To this is added a linear atomization
reaction for clusters of maximum size. The structure of the system is motivated
by models of gas evolution oscillators in physical chemistry, which exhibit
temporal oscillations under certain input/output conditions.
