Institute of Nano-Parthava, Mashhad, Iran.
Phys Chem Chem Phys. 2010 Dec 21;12(47):15372-81. doi: 10.1039/c004237d. Epub 2010 Oct 28.
Considering size effect on the equations obtained from statistical mechanical theories for the entropy of crystal and liquid phases, a new model has been developed for the melting entropy of nanocrystals, including the effects of the quasi-harmonic, anharmonic and electronic components of the overall melting entropy. Then with the use of our suggested new proportionality between the melting point and the entropy temperature (θ(0)), the melting entropy of nanocrystals has been obtained in terms of their melting point. Moreover, for the first time, the size-dependency of the electronic component of the overall melting entropy, arising from the change in the electronic ground-state of the nanocrystal upon melting, has been taken into account to calculate the melting entropy of nanocrystals. Through neglecting the effect of the electronic component, the present model can corroborate the previous model for size-dependent melting entropy of crystals represented by Jiang and Shi. The present model has been validated by the available computer simulation results for Ag and V nanoparticles. Moreover, a fairly constant function has been introduced which couples the melting temperature, the entropy temperature and the atomic density of elements to each other.
考虑到统计力学理论中晶体和液相熵方程的尺寸效应，我们为纳米晶体的熔化熵开发了一个新模型，包括准谐、非谐和整体熔化熵的电子分量的影响。然后，利用我们建议的新的熔点与熵温度（θ(0)）之间的比例关系，我们以熔点为依据得到了纳米晶体的熔化熵。此外，首次考虑了纳米晶体熔化时电子基态的变化引起的整体熔化熵的电子分量的尺寸依赖性，以计算纳米晶体的熔化熵。通过忽略电子分量的影响，本模型可以验证 Jiang 和 Shi 提出的代表晶体尺寸依赖性熔化熵的先前模型。本模型已通过可用的 Ag 和 V 纳米颗粒的计算机模拟结果进行了验证。此外，还引入了一个相当恒定的函数，将熔化温度、熵温度和元素的原子密度相互耦合。
