Gorelli F, Santoro M, Scopigno T, Krisch M, Ruocco G
Research Center SOFT-INFM-CNR, Università di Roma La Sapienza, I-00185, Roma, Italy.
Phys Rev Lett. 2006 Dec 15;97(24):245702. doi: 10.1103/PhysRevLett.97.245702. Epub 2006 Dec 13.
The high frequency dynamics of fluid oxygen has been investigated by inelastic x-ray scattering, at high pressures and room temperature. In spite of the markedly supercritical conditions (T approximately 2Tc, P>10(2)Pc), the sound velocity exceeds the hydrodynamic value of about 20%, a feature which is the fingerprint of liquidlike dynamics. The comparison of the present results with literature data obtained in several fluids allow us to identify the extrapolation of the liquid-vapor-coexistence line in the (P/Pc, T/Tc) plane as the relevant edge between liquidlike and gaslike dynamics. More interestingly, this extrapolation is very close to the non-metal-metal transition in hot dense fluids, at pressure and temperature values as obtained by shock wave experiments. This result points to the existence of a connection between structural modifications and transport properties in dense fluids.
在高压和室温下，通过非弹性X射线散射研究了液态氧的高频动力学。尽管处于明显的超临界条件下（T约为2Tc，P>10²Pc），声速仍超过流体动力学值约20%，这一特征是类液体动力学的标志。将当前结果与在几种流体中获得的文献数据进行比较，使我们能够确定在（P/Pc，T/Tc）平面中液-气共存线的外推是类液体动力学和类气体动力学之间的相关边界。更有趣的是，在冲击波实验获得的压力和温度值下，这种外推非常接近热致密流体中的非金属-金属转变。这一结果表明在致密流体中结构变化与输运性质之间存在联系。
