Liquid polyamorphism: Some unsolved puzzles of water in bulk, nanoconfined, and biological environments

摘要: We investigate the relation between changes in dynamic and thermodynamic anomalies arising from the presence of the liquid‐liquid critical point in (i) Two models of water, TIP5P and ST2, which display a first order liquid‐liquid phase transition at low temperatures; (ii) the Jagla model, a spherically symmetric two‐scale potential known to possess a liquid‐liquid critical point, in which the competition between two liquid structures is generated by repulsive and attractive ramp interactions; and (iii) A Hamiltonian model of water where the idea of two length/energy scales is built in; this model also displays a first order liquid‐liquid phase transition at low temperatures besides the first order liquid‐gas phase transition at high temperatures. We find a correlation between the dynamic fragility crossover and the locus of specific heat maxima (“Widom line”) emanating from the critical point. Our findings are consistent with a …