Figure 4.

Effect of the number of sites N on the cooperativity of the lattice, expressed by the maximum value of the binding capacity per site shown in Fig. 3. In the two-dimensional case (•) (1×1, 2×2, 3×3, 4×4, 5×5) the log–log plot is linear and implies a divergence of b_max according to N^a (a = 0.727 ± 0.002). This is conducive to a phase-transition-like discontinuity in the function b in the thermodynamic limit N → ∞. No such behavior is observed in the one-dimensional case (○) (N = 1, 4, 9, 16, 25). The value of the interaction constant is σ = 10.