The correlation between shape and size of linear chains on the simple cubic lattice is inmvestigated using a dynamic Monte Carlo technique.A positive correlation between the asphericity parameter A and the square of the end-to-end distance R^2 as well as that between A and the square of the radius of gyration S^2,is found for both RW and SAW chains,indicating that a chain conformation of small size is usually more spherical than one of large size.The result can explain why the shape of the SAW chain deviate much more from a sphere than that of the RW chain,and can also explain the similar dependence of size and shape on chain stiffness and on the distance of the first bead of a chain from an infinitely large flat surface.
