Nuclear quantum effects in a 1-D model of hydrogen bonded ferroelectrics
Nuclear quantum effects in a 1-D model of hydrogen bonded ferroelectrics
复制标题
氢键铁电体一维模型中的核量子效应
DOI：
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
K. T. Wikfeldt
中科院分区：
文献类型：
--
作者：
K. T. Wikfeldt
建立了一维氢键链耦合模型，并将其参数化，用于方酸（一种典型的氢键反铁电晶体）的密度泛函理论计算.由DFT得到的单个和集体质子跳跃的能量及其对H-键长的依赖性在模型中得到了很好的再现，尽管它很简单，其中只有氢和氧原子在（O-H）中的位置。O）H-键和H位置之间的最近邻耦合被明确包括在内。经典和路径积分分子动力学模拟揭示了核量子效应以及它们如何影响顺电相变。在转变温度TC处有很大的H/D同位素位移以及几何同位素效应，这与实验符合得很好。固定的O-O键长的结果在TC的位移到更高的温度，但TC的显着的同位素位移仍然存在，突出了量子效应的重要性超出了伴随同位素取代的氢键的几何变化。介于完全原子模型和更简单的伊辛型模型之间，建议的氢键链模型是一个有用的玩具模型，用于研究氢键铁电体相变背后的微观机制和量子涨落的详细作用。
A one dimensional model of a coupled hydrogen (H) bonding chain is developed and parametrized to density functional theory (DFT) calculations on squaric acid, a prototypical H-bonded antiferroelectric crystal. The energetics of single and collective proton jumps and its dependence on H-bond length, as obtained by DFT, is reproduced quite well in the model despite its simplicity where only hydrogen and oxygen atom positions in (O-H...O) H-bonds and nearest-neighbor coupling between H positions are explicitly included. Classical and path- integral molecular dynamics simulations are performed to shed light on nuclear quantum effects and how they influence the paraelectric phase transition. A large H/D isotope shift in the transition temperature TC as well as a geometric isotope effect is obtained in good agreement with experiment. Fixing the O-O bond length results in shifts of TC to higher temperature but a pronounced isotope shift of TC remains, highlighting the importance of quantum effects beyond the geometrical changes in H-bonds accompanying isotopic substitution. Intermediate between fully atomistic models and simpler Ising-type models, the proposed H-bond chain model is a useful toy model for investigating microscopic mechanisms behind phase transitions in H-bonded ferroelectrics and the detailed role of quantum fluctuations.
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影响因子：
3.4
作者：
Brewer, ML;Schmitt, UW;Voth, GA
通讯作者：
Voth, GA
影响因子：
8.6
作者：
C. Drechsel-Grau;D. Marx
通讯作者：
C. Drechsel-Grau;D. Marx
DOI：
10.1073/pnas.1016653108
发表时间：
2011-04-19
影响因子：
11.1
作者：
Li, Xin-Zheng;Walker, Brent;Michaelides, Angelos
通讯作者：
Michaelides, Angelos
使用中子散射和第一性原理密度泛函理论研究固体克罗康酸中的铁电行为
影响因子：
2.3
作者：
Mukhopadhyay S
通讯作者：
Mukhopadhyay S