  We propose a very simple but 'realistic' model of amphiphilic bilayers,simple
enough to be able to include a large number of molecules in the sample, but
nevertheless detailed enough to include molecular charge distributions,
flexible amphiphilic molecules and a reliable model of water. All these
parameters are essential in a nanoscopic scale study of intermolecular and long
range electrostatic interactions. We also propose a novel, simple and more
accurate macroscopic electrostatic field for model bilayers. This model goes
beyond the total dipole moment of the sample, which on a time average is zero
for this type of symmetrical samples, i. e., it includes higher order moments
of this macroscopic electric field. We show that by representing it with a
superposition of gaussians it can be 'analytically' integrated, and therefore
its calculation is easily implemented in a MD simulation (even in simulations
of non-symmetrical bi- or multi-layers). In this paper we test our model by
molecular dynamics simulations of Newton black films.
