Demmel F
ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom.
J Phys Condens Matter. 2018 Dec 12;30(49):495102. doi: 10.1088/1361-648X/aaeb72. Epub 2018 Nov 15.
Density fluctuations of liquid and 20 K undercooled gallium have been studied by neutron spectroscopy. The decay of density fluctuations has been recorded at the structure factor maximum over a wide temperature range up to twice the melting temperature. The amplitude of the scattering function falls off with rising temperature in a nonlinear way with a changing slope around [Formula: see text]. The derived generalized longitudinal viscosity shows an upturn with decreasing temperature in the same temperature range. This increase in viscosity can be understood that liquid gallium transforms from a more fluid liquid metal to a more viscous liquid metal in that temperature range upon cooling. The change in the amplitude shows a remarkable agreement with results from liquid aluminium, lead and rubidium. This study suggests a universal crossover in dynamics of liquid monatomic metals, despite the many peculiar properties of gallium.
通过中子光谱学研究了液态和20K过冷镓的密度涨落。在高达熔点温度两倍的宽温度范围内，在结构因子最大值处记录了密度涨落的衰减。散射函数的振幅随温度升高以非线性方式下降，在[公式：见原文]附近斜率发生变化。导出的广义纵向粘度在相同温度范围内随温度降低而上升。粘度的这种增加可以理解为液态镓在该温度范围内冷却时从流动性更强的液态金属转变为粘性更强的液态金属。振幅的变化与液态铝、铅和铷的结果显示出显著的一致性。这项研究表明，尽管镓有许多独特的性质，但液态单原子金属的动力学存在普遍的转变。
