We determined the shock equation of state of CaF2 at pressures of ∼0.4–1.5 TPa using high-power laser shock techniques. The shock velocity-particle velocity was approximated by the universal Hugoniot relationship known to metallic fluids. Our results do not support the incompressible behavior above ∼100 GPa claimed previously. Warm dense CaF2 is a bonded liquid above the melting point and approaches an ideal fluid above ∼1 TPa. The measured reflectivity change of CaF2 at the shock front, similar to the other semiconducting liquids in the warm dense region, suggests a gradual metallization process due to the presence of delocalized electrons at high shock-front temperatures.

中文翻译：

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激光冲击二氟化钙 (CaF2) 作为一种温暖的致密物质

我们使用高功率激光冲击技术确定了压力为 0.4-1.5 TPa 时 CaF2 状态的冲击方程。冲击速度-粒子速度近似于金属流体已知的通用 Hugoniot 关系。我们的结果不支持之前声称的 ∼100 GPa 以上的不可压缩行为。温暖致密的 CaF2 是熔点以上的键合液体，在约 1 TPa 以上接近理想流体。与温暖致密区域中的其他半导体液体类似，在激波前沿测得的 CaF2 反射率变化表明，由于在高激波前沿温度下离域电子的存在，金属化过程是逐渐的。