Anomaly of the temperature dependence of the diffusion of oxygen in supercritical water
Anomaly of the temperature dependence of the diffusion of oxygen in supercritical water
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DOI：
10.1063/1.1449863
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发表时间：
2002-02
影响因子：
4.4
通讯作者：
Tsutomu Ohmori;Y. Kimura
中科院分区：
文献类型：
--
作者：
Tsutomu Ohmori;Y. Kimura
利用分子动力学方法计算了氧分子在近超临界水和超临界水（SPCE模型）中的扩散常数。观测到DO2的反常温度依赖性：在115和217 kg m−3下，DO2随温度从647 K增加到773 K而减小。摩擦力对扩散的记忆函数表明，DO2主要由摩擦力的二进制部分控制，这与氧和水之间自由基分布函数的接触值密切相关。从773 K到647 K，该值随温度的降低而减小，这是DO2特有的温度依赖性的主要原因。
We have determined the diffusion constants of oxygen molecule (DO2) in near- and supercritical water (the SPCE model) over the wide density region by molecular dynamics simulations. Anomalous temperature dependence of DO2 has been observed: DO2 decreases with increasing temperature from 647 to 773 K at the 115 and 217 kg m−3. The memory function for the friction on the diffusion shows that DO2 is mainly dominated by the binary part of the friction, which is closely related to the contact value of the radical distribution function between oxygen and water. This value decreases with decreasing the temperature from 773 to 647 K, which is a main reason of the peculiar temperature dependence of DO2.