Figure 3: Evolution of the energy probability distribution of the VISAW.
From: First-order coil-globule transition driven by vibrational entropy
The first row portrays the evolution of the energy (per monomer) probability distribution for a fixed polymer length, N=180, and varying values of k (panel a: k=0, b: 0.02, c: 0.2 and d: 2). As it can be clearly seen, the distribution progressively broadens until two peaks become clearly discernible, signalling phase coexistence. The second row reports the evolution of the distribution for a fixed value of k (k=2) and progressively longer polymers (panel e: N=50, f: 100, g: 140 and h: 180). As for the first row, the distribution becomes broader and, eventually, characterized by two peaks. The behaviour of the VISAW model for k=0 and increasing lengths (i–l, same length sequence as for the second row) approaches the one of the standard ISAW model (dashed line), suggesting that the ISAW model and the VISAW model for k=0 belong to the same universality class.
