Małolepsza Edyta, Kim Jaegil, Keyes Tom
Department of Chemistry, Boston University, Boston, Massachusetts 02215-2521, USA.
Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.
Phys Rev Lett. 2015 May 1;114(17):170601. doi: 10.1103/PhysRevLett.114.170601. Epub 2015 Apr 28.
Metastable β ice holds small guest molecules in stable gas hydrates, so its solid-liquid equilibrium is of interest. However, aqueous crystal-liquid transitions are very difficult to simulate. A new molecular dynamics algorithm generates trajectories in a generalized NPT ensemble and equilibrates states of coexisting phases with a selectable enthalpy. With replicas spanning the range between β ice and liquid water, we find the statistical temperature from the enthalpy histograms and characterize the transition by the entropy, introducing a general computational procedure for first-order transitions.
亚稳态β冰在稳定的气体水合物中容纳小分子客体，因此其固液平衡备受关注。然而，水相晶体 - 液体转变很难模拟。一种新的分子动力学算法在广义NPT系综中生成轨迹，并通过可选择的焓使共存相的状态达到平衡。通过跨越β冰和液态水之间范围的复制品，我们从焓直方图中找到统计温度，并通过熵来表征转变，从而引入了一种用于一级转变的通用计算程序。
