Liquid Structure of Tantalum under Internal Negative Pressure

In situ femtosecond x-ray diffraction measurements and ab initio molecular dynamics simulations were performed to study the liquid structure of tantalum shock released from several hundred gigapascals (GPa) on nanosecond timescale. The results show that internal negative pressure applied reached $\ensuremath{-}5.6\text{ }(0.8)\text{ }\text{ }\mathrm{GPa}$, suggesting existence a liquid-gas mixing state due cavitation. This is first direct evidence prove classical nucleation theory which predicts liquids with high surface tension can support GPa regime tensile stress.