Despite its long history, there are many fundamental issues concerning random packings of spheres that remain elusive, including a precise definition close packing (RCP). We argue the current picture RCP cannot be made mathematically and support this conclusion via molecular dynamics study hard using Lubachevsky-Stillinger compression algorithm. suggest impasse can broken by introducing new concept maximally jammed state, which precise.

The anomalous properties of cold and supercooled water, such as the fact that at sufficiently low temperatures it becomes more compressible less dense when cooled, fluid compressed, have attracted attention physical scientists for a long time. discovery in 1970s several thermodynamic transport water exhibit pronounced temperature dependence appear to diverge slightly below homogeneous nucleation inspired large number experimental theoretical studies. Likewise, an important body work on...

The pronounced increases in isothermal compressibility, isobaric heat capacity, and the magnitude of thermal expansion coefficient liquid water upon supercooling have been interpreted either terms a continuous, retracing spinodal curve bounding superheated, stretched, supercooled states water, or metastable, low-temperature critical point. Common to these two scenarios is existence singularities associated with diverging density fluctuations at low temperature. We show that increase...

Cold, noncrystalline states play an important role in understanding the physics of liquid water. From recent experimental and theoretical investigations, a coherent interpretation water’s properties is beginning to emerge.

We perform molecular dynamics simulations of water in the presence hydrophobic/hydrophilic walls at T = 300 K and P 0 GPa. For hydrophilic walls, we use a hydroxylated silica model introduced previous [Lee, S. H.; Rossky, P. J. Chem. Phys. 1994, 100, 3334. Giovambattista, N.; J.; Debenedetti, G.; Rev. E 2006, 73, 041604.]. By rescaling physical partial atomic charges by parameter ≤ k 1, can continuously transform (hydroxylated silica, 1) into hydrophobic apolar surfaces (k 0). From point...

We perform systematic molecular dynamics simulations of water confined between two nanoscale plates at $T=300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. investigate the effect pressure $(\ensuremath{-}0.15\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}\ensuremath{\leqslant}P\ensuremath{\leqslant}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{GPa})$ and plate separation $(0.4\phantom{\rule{0.3em}{0ex}}\mathrm{nm}\ensuremath{\leqslant}d\ensuremath{\leqslant}1.6\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ on phase...

The remarkable kinetic slowdown experienced by liquids as they are cooled toward their glass transition is not accompanied any obvious structural change. Understanding the origin of this behavior a major scientific challenge. At present, area condensed matter theory characterized an abundance divergent viewpoints that attempt to describe well-defined physical phenomena. We review representative theoretical views on unusual kinetics liquid supercooling, which fall into two broad competing...

The hypothesis that water has a second critical point at deeply supercooled conditions was formulated to provide thermodynamically consistent interpretation of numerous experimental observations. A large body work been devoted verifying or falsifying this hypothesis, but no unambiguous proof yet found. Here, we use histogram reweighting and large-system scattering calculations investigate computationally two molecular models water, TIP4P/2005 TIP4P/Ice, widely regarded be among the most...

Ice formation is ubiquitous in nature, with important consequences a variety of environments, including biological cells, soil, aircraft, transportation infrastructure and atmospheric clouds. However, its intrinsic kinetics microscopic mechanism are difficult to discern current experiments. Molecular simulations ice nucleation also challenging, direct rate calculations have only been performed for coarse-grained models wate. For molecular models, indirect estimates obtained, e.g. by assuming...

The possible existence of a metastable liquid-liquid transition (LLT) and corresponding critical point (LLCP) in supercooled liquid water remains topic much debate. An LLT has been rigorously proved three empirically parametrized molecular models water, evidence consistent with an reported for several other such models. In contrast, experimental proof this phenomenon elusive due to rapid ice nucleation under deeply conditions. work, we combined density functional theory (DFT), machine...

Molecular simulations have provided valuable insight into the microscopic mechanisms underlying homogeneous ice nucleation. While empirical models been used extensively to study this phenomenon, based on first-principles calculations so far proven prohibitively expensive. Here, we circumvent difficulty by using an efficient machine-learning model trained density-functional theory energies and forces. We compute nucleation rates at atmospheric pressure, over a broad range of supercoolings,...

For the past 50 years, researchers have sought molecular models that can accurately reproduce water's microscopic structure and thermophysical properties across broad ranges of its complex phase diagram. Herein, dynamics simulations with many-body MB-pol model are performed to monitor thermodynamic response functions local liquid water from boiling point down deeply supercooled temperatures at ambient pressure. The isothermal compressibility isobaric heat capacity show maxima near 223 K, in...

This paper examines the prospects for quantifying disorder in simple molecular or colloidal systems. As a central element this task, scalar measures describing both translational and bond-orientational order are introduced. These subsequently used to characterize structures that result from series of molecular-dynamics simulations hard-sphere system. The simulation results can be illustrated by two-parameter ordering phase diagram, which indicates relative placement equilibrium phases...

Measurement of the rates evaporation amorphous water (a) and ice (i) near 150 K can be interpreted as giving a measure their free energy difference, ΔaiG (150 K)=1100±100 J/mol, which, together with known enthalpy difference heat capacity data, suggests residual entropy ΔaiS (0)=−0.7±2.2 J/(K mol) at absolute zero. Previous theoretical estimates (0), which are much larger, did not allow amorph to connected normal liquid by reversible thermodynamic path atmospheric pressure. The present value...

To better understand the role of surface chemical heterogeneity in natural nanoscale hydration, we study via molecular dynamics simulation structure and thermodynamics water confined between two protein-like surfaces. Each is constructed to have interactions with corresponding those putative hydrophobic a melittin dimer, but flattened rather than having its native "cupped" configuration. Furthermore, peripheral charged groups are removed. Thus, rough topography removed, results can be...