Abramson Evan H
Department of Earth and Space Sciences, University of Washington , Seattle, Washington 98195-1310, United States.
J Phys Chem B. 2014 Oct 9;118(40):11792-6. doi: 10.1021/jp5079696. Epub 2014 Sep 25.
Shear viscosities of supercritical nitrogen have been measured in the high-pressure diamond-anvil cell, to 673 K and pressures in excess of 10 GPa, using a rolling-sphere technique. The entire set of data, along with lower pressure data from the literature, can be fit to a two-parameter expression in reduced viscosity and reduced residual entropy. The fit spans densities from the dilute gas to 5x the critical density, and two orders magnitude in temperature and in viscosity, with a maximum deviation of 20%. Reduced viscosities scale as ρ(4)/T and comport with the theory of state "isomorphs" for "Roskilde-simple" systems. The new data allow direct comparison with results of molecular dynamic simulations at high densities.
利用滚动球技术，在高压金刚石对顶砧池中测量了超临界氮的剪切粘度，测量温度范围至673K，压力超过10GPa。整套数据，连同来自文献的低压数据，都可以拟合为一个关于对比粘度和对比剩余熵的双参数表达式。该拟合涵盖了从稀薄气体到5倍临界密度的密度范围，以及两个数量级的温度和粘度范围，最大偏差为20%。对比粘度按ρ(4)/T缩放，并与“罗斯基勒简单”系统的状态“同构体”理论相符。新数据允许与高密度下的分子动力学模拟结果进行直接比较。
