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arXiv physics/0207068physics.atm-cluscond-mat.mtrl-sciphysics.chem-ph
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钠原子团簇的熔化

Melting of sodium clusters

Juan A. Reyes-Nava, Ignacio L. Garzon, Marcela R. Beltran, Karo Michaelian

摘要:

用微正则分子动力学模拟研究了Na_n(n=13-147)团簇的热稳定性和类熔化转变。钠团簇中的金属键是由基于紧束缚哈密顿量的二阶矩近似的多体Gupta势模拟的。钠团簇中的固-液转变的特征通过计算物理量如热量曲线、热容和均方根键长波动使用几纳秒的模拟时间来分析。不同的熔融机制,得到的钠簇的尺寸范围内的调查。计算的熔化温度随团簇尺寸呈不规则变化,与最近的实验结果定性一致。然而,Na_(55)团簇的计算熔点比实验值低约40%.

英文摘要:

Thermal stability properties and the melting-like transition of Na_n, n=13-147, clusters are studied through microcanonical molecular dynamics simulations. The metallic bonding in the sodium clusters is mimicked by a many-body Gupta potential based on the second moment approximation of a tight-binding Hamiltonian. The characteristics of the solid-to-liquid transition in the sodium clusters are analyzed by calculating physical quantities like caloric curves, heat capacities, and root-mean-square bond length fluctuations using simulation times of several nanoseconds. Distinct melting mechanisms are obtained for the sodium clusters in the size range investigated. The calculated melting temperatures show an irregular variation with the cluster size, in qualitative agreement with recent experimental results. However, the calculated melting point for the Na_55 cluster is about 40 % lower than the experimental value.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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