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

We present a Monte Carlo finite-size scaling analysis of the Pink model with the fitted parameters appropriate for dipalmitoyl phosphatidylcholine and disteroyl phosphatidylcholine lipid-bilayer systems. The numerical simulations were performed in conjunction with the extrapolation 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 there is no first-order phase transition and that the abrupt jump in the order parameter and the enhancement of the response functions found by previous numerical simulations are due to the presence of strong lateral density fluctuations which give rise to a large correlation length.