论文标题
等温线和绝热弹性常数来自病毒波动
Isothermal and adiabatic elastic constants from virial fluctuations
论文作者
论文摘要
我们为周期系统的经典等温和绝热弹性常数提供了明确包括边界贡献的表达式。这些表达式的潜在依赖部分是根据构成总势能的原子群的势能编写的。结果表明，在热力学极限中，依赖于势能的第二个衍生物的诞生项可以按照涉及两种类型的原子组病毒的平均值来表达。结果，出生术语的新形式仅涉及原子组或总势能的第一衍生物。使用晶体氩和硅的分子动力学模拟对涉及两种出生项的两种形式的派生弹性常数表达式进行了测试。对于这两种材料，使用出生术语的两种形式获得的弹性常数非常同意。特别是，诞生术语的新形式收敛到与原始术语相同的值，但速率较慢。硅的结果也与先前分子动力学研究的结果一致。
We derive expressions for classical isothermal and adiabatic elastic constants for periodic systems with the boundary contributions included explicitly. The potential-dependent part of these expressions is written in terms of potential energies of atomic groups that make up the total potential energy. It is shown that in the thermodynamic limit, the Born term, which depends on the second derivatives of potential energy, can be expressed exactly in terms of equilibrium averages that involve two types of atomic-group virials. As a result, the new form of the Born term involves only first derivatives of either atomic-group or total potential energies. The derived elastic constant expressions involving the two forms of the Born terms are tested and compared using molecular-dynamics simulations of crystalline argon and silicon. For both materials, the elastic constants obtained using the two forms of the Born term are in good agreement. In particular, the new form of the Born term converges to the same value as the original Born term but at a slower rate. The results for silicon also agree well with the results from the previous molecular-dynamics studies.
