水の2つの現実的なモデルにおける第2の臨界点
Pablo G Debenedetti1, Francesco Sciortino2, Gül H Zerze3
1Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA. pdebene@princeton.edu.
まとめ
超冷却した水の第二の臨界点を 計算研究で明らかにしました TIP4P/2005とTIP4P/Iceの両モデルは,Ising普遍性と一致する,メタスタブルな液体-液体の臨界点を示しています.
科学分野:
- 物理化学
- 計算物理
- 熱力学について
背景:
- 二つ目の臨界点の存在は 深刻に超冷却された水では 未解決の重要な問題です
- 数多くの実験的観測が その存在を示唆していますが 直接的な明確な証拠は欠けています
- この臨界点は,低温での水の異常な振る舞いを説明する仮説である.
研究 の 目的:
- 水中の第2の臨界点の仮説を計算的に調査する.
- TIP4P/2005とTIP4P/Iceの2つの著名な分子モデルの振る舞いを超冷却条件下で分析する.
- これらのモデルが液体-液体の臨界点の存在を支持するかどうかを判断する.
主な方法:
- 統計的正確性を高めるため,ヒストグラムの重量調整技術を使用した.
- 液体の構造を調べるため,大規模な分散計算を行いました.
- 水の分子モデルをシミュレートするために高度な計算方法を採用しました.
主要な成果:
- TIP4P/2005とTIP4P/Iceの両モデルは,メタスタブルな液体-液体の臨界点を示しています.
- この臨界点は,相図の超冷却領域に位置する.
- 観測された批判的行動は,三次元のイッシング普遍性クラスの予測と一致する.
結論:
- 計算上の発見は水における第2の臨界点という仮説を支持している.
- この結果はTIP4P/2005とTIP4P/氷のモデルがこの現象を捉える正確さを検証しています.
- この研究は,イージングの普遍性クラスが水の重要な振る舞いを支配する強力な証拠を提供します.
さらに関連する動画
10:52Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
Published on: April 12, 2019
13.2K
12:11Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
8.6K
関連する概念動画
Phase Diagrams
47.7K
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
47.7K
States of Water
55.6K
Water exists in any one of the three classical states: solid (ice), liquid (water), and gas (steam or water vapor). The state of water depends on i) the intermolecular forces that draw molecules together and ii) the kinetic energy that leads to movements that pull them apart.
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
55.6K
Phase Diagram
6.8K
The phase of a given substance depends on the pressure and temperature. Thus, plots of pressure versus temperature showing the phase in each region provide considerable insights into the thermal properties of substances. Such plots are known as phase diagrams. For instance, in the phase diagram for water (Figure 1), the solid curve boundaries between the phases indicate phase transitions (i.e., temperatures and pressures at which the phases coexist).
6.8K
Role of Water in Human Biology
12.3K
Water is the one of the most significant components of the human body; it plays a crucial role in several physiological activities because of its unique physicochemical properties. Importantly, it helps to regulate body temperature and is the chief component of several body fluids.
Water's Solvent Properties
Since water is a polar molecule with slightly positive and slightly negative charges, ions and polar molecules can readily dissolve in it. Therefore, it is referred to as a solvent, a...
Water's Solvent Properties
Since water is a polar molecule with slightly positive and slightly negative charges, ions and polar molecules can readily dissolve in it. Therefore, it is referred to as a solvent, a...
12.3K
pV-Diagrams
5.8K
The pV diagram, which is a graph of pressure versus volume of the gas under study, is helpful in describing certain aspects of the substance. When the substance behaves like an ideal gas, the ideal gas equation describes the relationship between its pressure and volume. On a pV diagram, it is common to plot an isotherm, which is a curve showing p as a function of V with the number of molecules and the temperature fixed. Then, for an ideal gas, the product of the pressure of the gas and its...
5.8K
Solubility Equilibria: Ionic Product of Water
1.4K
Pure water is a weak electrolyte; only a small amount ionizes into hydrogen and hydroxide ions. At any given temperature, the concentration of undissociated water is almost constant, so the ionic product of water is the product of the hydrogen and hydroxide ion concentrations, denoted as Kw. The square root of Kw gives the individual ion concentrations.
The ionic product of water varies with temperature, and its value is 1.0 x 10−14 at standard experimental conditions. Per Le...
The ionic product of water varies with temperature, and its value is 1.0 x 10−14 at standard experimental conditions. Per Le...
1.4K
