Examination of the theta -point from exact enumeration of self-avoiding walks

Abstract

Self-avoiding walks on the square lattice with nearest-neighbour attractive interactions are investigated as a model for the two-dimensional version of a polymer in dilute solution. Temperature dependences of the exponent nu and the free energy of the chain are estimated from the exact enumeration data for up to 20 steps; the value of nu at the theta -point disagrees with the mean-field theory. The end-distance distribution function at the theta -point is also examined.