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arXiv 0911.3188cond-mat.mtrl-sci
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如何量化固体的能量景观

How to quantify energy landscapes of solids

Artem R. Oganov, Mario Valle

摘要:

我们探讨是否在化学系统中的能量景观的拓扑结构服从任何规则,这些规则是什么。为了回答这个问题和相关的问题,我们使用几个工具:(i)约化的能量表面及其状态密度,(ii)称为指纹函数的结构描述符,其可以表示为一维函数或抽象多维空间中的向量,(iii)定义两个结构之间的“距离",使得能够量化能量景观,(iv)定义结构的有序度,以及(v)量化结构多样性的准熵的定义。我们的方法可用于合理化大型数据库的晶体结构和调整计算算法的结构预测。它可以定量和直观地表示能源景观,并重新评估一些传统的化学概念和规则。我们的分析证实了预期的低能量的最小值聚集在紧凑的区域的配置空间(“漏斗”)和化学系统往往有很少的漏斗,有时只有一个。这种分析可以应用于固体的物理性质,开辟了发现结构-性质关系的新途径。我们定量地表明,晶体往往采用少数最简单的结构与它们的化学性质相一致,提供了热力学理由鲍林第五规则。

英文摘要:

We explore whether the topology of energy landscapes in chemical systems obeys any rules and what these rules are. To answer this and related questions we use several tools: (i)Reduced energy surface and its density of states, (ii) descriptor of structure called fingerprint function, which can be represented as a one-dimensional function or a vector in abstract multidimensional space, (iii) definition of a ''distance'' between two structures enabling quantification of energy landscapes, (iv) definition of a degree of order of a structure, and (v) definitions of the quasi-entropy quantifying structural diversity. Our approach can be used for rationalizing large databases of crystal structures and for tuning computational algorithms for structure prediction. It enables quantitative and intuitive representations of energy landscapes and reappraisal of some of the traditional chemical notions and rules. Our analysis confirms the expectations that low-energy minima are clustered in compact regions of configuration space ("funnels") and that chemical systems tend to have very few funnels, sometimes only one. This analysis can be applied to the physical properties of solids, opening new ways of discovering structure-property relations. We quantitatively demonstrate that crystals tend to adopt one of the few simplest structures consistent with their chemistry, providing a thermodynamic justification of Pauling's fifth rule.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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