Department of Nuclear Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (MIFT), Università di Messina, 98166 Messina, Italy.
Int J Mol Sci. 2019 Oct 29;20(21):5373. doi: 10.3390/ijms20215373.
The hydrogen density of states (DOS) in confined water has been probed by inelastic neutron scattering spectra in a wide range of its - phase diagram. The liquid-liquid transition and the dynamical crossover from the fragile (super-Arrhenius) to strong (Arrhenius) glass forming behavior have been studied, by taking into account the system polymorphism in both the liquid and amorphous solid phases. The interest is focused in the low energy region of the DOS ( E < 10 meV) and the data are discussed in terms of the energy landscape (local minima of the potential energy) approach. In this latest research, we consider a unit scale energy (EC) linked to the water local order governed by the hydrogen bonding (HB). All the measured spectra, scaled according to such energy, evidence a universal power law behavior with different exponents ( γ ) in the strong and fragile glass forming regions, respectively. In the first case, the DOS data obey the Debye squared-frequency law, whereas, in the second one, we obtain a value predicted in terms of the mode-coupling theory (MCT) ( γ ≃ 1.6 ).
通过在其 - 相图的广泛范围内进行非弹性中子散射光谱，研究了受限水中的氢态密度（DOS）。考虑到液体和非晶固体相中的系统多态性，研究了液体-液体转变和从脆弱（超阿累尼乌斯）到强（阿累尼乌斯）玻璃形成行为的动力学交叉。研究集中在 DOS 的低能区域（E < 10 meV），并根据能量景观（势能的局部最小值）方法讨论数据。在这项最新研究中，我们考虑了一个与氢键（HB）控制的水局部有序相关的单位尺度能量（EC）。根据该能量进行缩放的所有测量光谱，在强和脆弱的玻璃形成区域分别表现出不同指数（γ）的普遍幂律行为。在第一种情况下，DOS 数据遵循德拜平方频率定律，而在第二种情况下，我们根据模式耦合理论（MCT）（γ≈1.6）获得了一个预测值。
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