Potential Renormalization Theory Mapping Interatomic Forces onto Lattice Models

将原子间力映射到晶格模型上的势重正化理论

基本信息

批准号：
13650714
负责人：
OHNO Kaoru
金额：
$ 2.69万
依托单位：
Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650714/
关键词：
Renormalized Potential Molecular Dynamics Method Monte Carlo Simulation Lattice Gas Model Partition Function Order-Disorder Transition Phase Transition Semi-Flexible Polymer Solution 半屈曲高分子溶液半屈曲性高分子鎖溶液

项目摘要

Atomic diffusion and order-disorder phase transition in substitutional alloys are very long-time-scale phenomena, which are far beyond the limit of applying the molecular dynamics simulations. Such phenomena can be more effectively treated in the lattice-gas models. On a completely new intuition that the partition function of the original off-lattice system should coincide with that of the lattice-gas model, we have proposed "the potential renormalization theory", which can deduce the interaction parameters of the corresponding lattice-gas model. We have applied this theory to the silicon crystal and the Cu_xAu_<1-x> alloy. That is, we have determined the interaction parameters at various temperatures by means of the potential renormalization theory and performed the lattice Monte Carlo simulations of the lattice-gas model with the resulting interaction parameters. Thus obtained thermal expansion coefficients and melting temperature of silicon agree well with the result of the preexisting molecular dynamics simulations. Moreover, the obtained phase diagram related to the order-disorder phase transition of the Cu_xAu<1-x> alloy for various compositions x reproduces well the experimental phase diagram. This latter result has recently published in J.Crystal Growth. On the other hand, we have applied this theory to the investigation of semi-flexible polymer solution and revealed that the stiffness of polymers depends on the temperature. We reported it at the ICAM-IUMRS held in Yokohama on Oct.8-13(2003). It is now highly desirable to apply this powerful method to many other systems.

替代合金中的原子扩散和秩序相变是很长的现象，它们远远超出了应用分子动力学模拟的极限。这种现象可以在晶格 - 气体模型中更有效地处理。在一个全新的直觉上，原始非晶格系统的分区函数应与晶格 - 加拿大模型的分区函数相吻合，我们提出了“潜在的重新归一化理论”，该理论可以推断出相应的晶状体加速器模型的相互作用参数。我们已经将该理论应用于硅晶体和cu_xau_ <1-x>合金。也就是说，我们通过潜在的重新规定理论确定了在各种温度下的相互作用参数，并通过产生的相互作用参数进行了晶状体加速器模型的晶格蒙特卡洛模拟。因此获得的热膨胀系数和硅的熔化温度与先前存在的分子动力学模拟的结果非常吻合。此外，获得的相图与cu_xau <1-x>合金的各种组合物x x的阶阶相变相关，可以很好地重现实验相图。后一种结果最近发表在J.Crystal的生长中。另一方面，我们已将该理论应用于半柔性聚合物溶液的研究，并揭示了聚合物的刚度取决于温度。我们在10月8日至13日在横滨（2003）在横滨举行的ICAM-IMRS进行了报告。现在，非常希望将这种强大的方法应用于许多其他系统。