Molecular dynamics study of thermal expansion and compression in spin-crossover solids using a microscopic model of elastic interactions
Molecular dynamics study of thermal expansion and compression in spin-crossover solids using a microscopic model of elastic interactions
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DOI：
10.1103/physrevb.79.012409
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发表时间：
2009-01-01
影响因子：
3.7
通讯作者：
Miyashita, Seiji
中科院分区：
文献类型：
--
作者：
Nishino, Masamichi;Boukheddaden, Kamel;Miyashita, Seiji
我们研究了自旋交叉固体的体积和高自旋分数的温度和压力依赖性的特征。我们发展了一个等压-等温系综中的分子动力学模型和方法来处理分子内完全对称模的运动，同时考虑了其他模的熵效应。我们发现了一些有趣的观察结果，例如，体积的非单调温度依赖性。在实验中经常观察到的激发高自旋态（光诱导态）的S形弛豫在MD的确定性动力学中被自动再现，尽管以前已经通过假设随机动力学中的Arrhenius跃迁概率进行了研究。
We study characteristic features of the temperature and pressure dependences of the volume and high-spin fraction of spin-crossover solids. We develop a model and method of molecular dynamics (MD) in the isobaric-isothermal ensemble to treat the motion of the intramolecular totally symmetric mode, taking into account the entropy effect from other modes. We find several interesting observations, e.g., a nonmonotonic temperature dependence of the volume. Sigmoidal relaxations from the excited high-spin state (photoinduced state), which were often observed in experiments, are automatically reproduced in the present deterministic dynamics of MD, although it has previously been studied by assuming Arrhenius transition probabilities in stochastic dynamics.