  The critical point of the condensation transition for linear molecules
adsorbed on square lattices, was studied by using an adaptation of the
Histogram Reweighting technique. The results were obtained by means of grand
canonical Monte Carlo simulations within the lattice gas model, along with
finite size scaling using the fourth order Binder cumulant. The Method was
tested in a system of interacting monomers in which the critical point can be
determined exactly. The application of this method to the determination of the
critical point in dimer systems with attractive interactions, gave better
results than the previous reported studies to the best knowledge of the
authors. In addition, the adsorption isotherms at different temperatures, as
well as the phase diagrams for monomer and dimer systems were obtained,
achieving significant improvements in the phase diagram for dimers.
