Thermal conductivities of molecular liquids by reverse nonequilibrium molecular dynamics.
Thermal conductivities of molecular liquids by reverse nonequilibrium molecular dynamics.
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DOI：
10.1021/jp0512255
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发表时间：
2005-07
期刊：
影响因子：
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通讯作者：
Meimei Zhang;E. Lussetti;Luís E S de Souza;F. Müller-Plathe
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文献类型：
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作者：
Meimei Zhang;E. Lussetti;Luís E S de Souza;F. Müller-Plathe
热导率的反向非平衡分子动力学方法适用于分子流体的研究。该方法通过适当地交换位于不同区域的粒子的速度来产生通过系统的热流。根据得到的温度梯度，然后计算导热系数。测试了算法的不同变体及其与其他系统参数的组合：原子速度交换与分子质心速度交换、不同交换频率、具有键约束的分子模型与具有柔性键的模型、联合原子与全原子模型、以及存在或不存在恒温器。为了帮助确定适用范围，该算法在苯、环己烷、水和正己烷的不同模型上进行了测试。我们发现，该算法是稳健的，并且计算的导热系数对其控制参数的变化不敏感。相反，力场对导热系数的值有很大影响。虽然计算的导热系数和实验的导热系数属于相同的数量级，但在大多数情况下，计算值要大得多。联合原子力场似乎比全原子力场做得更好，可能是因为它们从模拟中去除了高频自由度，而高频自由度实际上是处于基态的量子力学振荡器，对热传导没有贡献。
The reverse nonequilibrium molecular dynamics method for thermal conductivities is adapted to the investigation of molecular fluids. The method generates a heat flux through the system by suitably exchanging velocities of particles located in different regions. From the resulting temperature gradient, the thermal conductivity is then calculated. Different variants of the algorithm and their combinations with other system parameters are tested: exchange of atomic velocities versus exchange of molecular center-of-mass velocities, different exchange frequencies, molecular models with bond constraints versus models with flexible bonds, united-atom versus all-atom models, and presence versus absence of a thermostat. To help establish the range of applicability, the algorithm is tested on different models of benzene, cyclohexane, water, and n-hexane. We find that the algorithm is robust and that the calculated thermal conductivities are insensitive to variations in its control parameters. The force field, in contrast, has a major influence on the value of the thermal conductivity. While calculated and experimental thermal conductivities fall into the same order of magnitude, in most cases the calculated values are systematically larger. United-atom force fields seem to do better than all-atom force fields, possibly because they remove high-frequency degrees of freedom from the simulation, which, in nature, are quantum-mechanical oscillators in their ground state and do not contribute to heat conduction.