The macroscopic stress formulation for periodic systems in Kohn–Sham density functional theory is critically examined. The identification of the stress through the partial variation of the energy with respect to cell deformation is cast in a strictly large deformation context. The nature of the non-uniqueness in the stress expression which emanates from this variation is extensively discussed. The possible lack of symmetry in this expression is highlighted and the conditions under which different expressions deliver the same tensorial value are derived. These observations are demonstrated through a finite element framework that is validated towards energy, force and stress calculations.

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关于 Kohn-Sham 密度泛函理论中宏观应力的识别和有限元处理


对 Kohn-Sham 密度泛函理论中周期系统的宏观应力公式进行了批判性检查。通过能量相对于电池变形的部分变化来识别应力是在严格的大变形背景下铸造的。由这种变化引起的应力表达的非唯一性的性质得到了广泛的讨论。突出显示了此表达式中可能缺乏对称性，并推导出不同表达式提供相同张量值的条件。这些观察结果通过有限元框架进行验证，该框架在能量、力和应力计算中得到了验证。