We study the quantum nature of the protons participating in hydrogen bonds in several ice structures by analyzing the one particle density matrix. We find that in all cases, including ice Ih, the most common form of ice, and the high pressure phases, ice VIII, VII, and X, the system is ground-state dominated. However, while the dynamics is uncorrelated in the structures with standard asymmetric...

We studied the thermodynamics of a homopolymeric chain with both van der Waals and directed hydrogen bond interaction. The effect of hydrogen bonds is to reduce dramatically the entropy of low-lying states and to give rise to long-range order and to conformations displaying secondary structures. For compact polymers a transition is found between helix-rich states and low-entropy sheet-dominated...

The kinetics of forming and breaking water-water hydrogen bonds in neat water, an aqueous solution of ethane, and an aqueous solution of NaCl are studied by molecular dynamics simulations. We compare nonpolarizable and polarizable water models to elucidate the effect of water’s polarizability on hydrogen bonds. We find that polarizability strengthens the hydrogen bonds and increases the hydroge...