Diffusion activation energy versus the favourable energy in two-order-parameter model- A molecular dynamics study of liquid Al

In the present work, we find that both diffusion activation energy Ea（D） and Ea（S^ex） increase linearly with pressure and have the same slope （0.022±0.001 eV/GPa） for liquid Al. The temperature and pressure dependence of excess entropy is well fitted by the expression -S^ex （T, P）/kB = a（P）＋ b（P）T ＋...

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Published inChinese physics B Vol. 19; no. 8; pp. 483 - 488
Main Author 李宜德 郝清海 曹启龙 刘长松
Format Journal Article
LanguageEnglish
Published IOP Publishing 01.08.2010
Subjects
Activation energy
Aluminum
Diffusion
Entropy
Liquids
Molecular dynamics
Pressure dependence
Sex
分子动力学模拟
压力
参数模型
大肠杆菌
扩散活化能
液态铝
能源
行动纲领
Online AccessGet full text
ISSN1674-1056
2058-3834
DOI10.1088/1674-1056/19/8/086104

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Summary:In the present work, we find that both diffusion activation energy Ea（D） and Ea（S^ex） increase linearly with pressure and have the same slope （0.022±0.001 eV/GPa） for liquid Al. The temperature and pressure dependence of excess entropy is well fitted by the expression -S^ex （T, P）/kB = a（P）＋ b（P）T ＋ c（P） exp（Ef/kBT）, which together with the small ratio of Ef/kB T leads to the relationship of excess entropy to temperature and pressure, i.e. Sex ~ -cEf/T, where c is about 12 and Ef （= △E - P△V） is the favourable energy. Therefore, there exists a simple relation between Ea（S^ex） and Ef, i.e. Ea（S^ex） ≈ cEf.
Bibliography:TF704.3
TP212
activation energy, favourable energy, molecular dynamics simulation
11-5639/O4
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ISSN:1674-1056
2058-3834
DOI:10.1088/1674-1056/19/8/086104