Conformational properties of polymer chains in the theta region

A configurational bias Monte Carlo algorithm has been employed to investiga te the conformational properties of an off-lattice polymer chain model clos e to the theta point. In particular, we have extended previous results for the chain's mean size and shape to longer chains, allowing for a more detai led comparison with field renormalization group theory. Moreover, we presen t the first data of internal energy and specific heat for this type of off- lattice model, showing the approach to the expected theoretical behavior. ( C) 1999 American Institute of Physics. [S0021-9606(99)51425-6].