Ashcraft R, Wang Z, Abernathy D L, Quirinale D G, Egami T, Kelton K F
Department of Physics, Washington University, St. Louis, Missouri 63130, USA.
Department of Materials Science and Engineering, Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.
J Chem Phys. 2020 Feb 21;152(7):074506. doi: 10.1063/1.5144256.
Even though the viscosity is one of the most fundamental properties of liquids, the connection with the atomic structure of the liquid has proven elusive. By combining inelastic neutron scattering with the electrostatic levitation technique, the time-dependent pair-distribution function (i.e., the Van Hove function) has been determined for liquid ZrPt. We show that the decay time of the first peak of the Van Hove function is directly related to the Maxwell relaxation time of the liquid, which is proportional to the shear viscosity. This result demonstrates that the local dynamics for increasing or decreasing the coordination number of local clusters by one determines the viscosity at high temperature, supporting earlier predictions from molecular dynamics simulations.
尽管粘度是液体最基本的性质之一，但事实证明，它与液体的原子结构之间的联系难以捉摸。通过将非弹性中子散射与静电悬浮技术相结合，已确定了液态ZrPt的时间相关对分布函数（即范霍夫函数）。我们表明，范霍夫函数第一个峰的衰减时间与液体的麦克斯韦弛豫时间直接相关，而麦克斯韦弛豫时间与剪切粘度成正比。这一结果表明，通过增加或减少局部团簇的配位数一个来改变局部动力学决定了高温下的粘度，支持了分子动力学模拟的早期预测。
