APPLICATION OF FINITE-SIZE SCALING TO THE PINK MODEL FOR LIPID BILAYERS

We present a Monte Carlo finite-size scaling analysis of the Pink mode l with the fitted parameters appropriate for dipalmitoyl phosphatidylc holine and disteroyl phosphatidylcholine lipid-bilayer systems. The nu merical simulations were performed in conjunction with the extrapolati on method of Ferrenberg and Swendsen [Phys. Rev. Lett. 61, 2635 (1988) ] and the finite-size scaling method of Lee and Kosterlitz [Phys. Rev. Lett. 65, 137 (1990)]. In contrast to previous work, we found that th ere is no first-order phase transition and that the abrupt jump in the order parameter and the enhancement of the response functions found b y previous numerical simulations are due to the presence of strong lat eral density fluctuations which give rise to a large correlation lengt h.