Abstract: A large number of particles evaporated from liquid iodine deposited on the wall of a glass container. The deposits demonstrate three structural shapes:globule chain,network formation,and dendrite. The globule chain displays clearly self-similar feature,and can be characterized by fractal geometry. The fractal dimension of the globule chain patterns ranges from D=1.50 to 1.75.The in situ sublimat- ing process of an iodine fractal aggregate was observed.It revealed reversal of the random growth process under nonequilibrium condition.The analytical results show that the nucleation-aggregation (NA) model can explain the growth process of iodine fractal aggregate.

Key words: iodine, fractal aggregation, nonequilibrium