Molecular dynamics calculation of properties of liquid lead and bismuth under shock compression

The embedded atom model (EAM) potentials are proposed, enabling the description of liquid lead and bismuth under conditions typical of shock compression. The potentials reported earlier to describe metals under pressures close to normal and experimental data on shock compression are used. The contributions of collective electrons to energy and pressure are taken into account. Series of models are constructed of $2048$ or $2000$ atoms in a basic cube at compression ratios $Z$ down to $0.5$ of the initial volume under pressures up to $280$ GPa and temperatures up to $24 850$ K. These potentials give an adequate description of liquid lead and bismuth in these conditions. The thermodynamic properties of the metals at $Z = 1.0$–$0.5$ and temperatures up to $20 000$ K are calculated and presented in tables. The cold pressures for states at a temperature of $298$ K are evaluated. Using the embedded atom potential of lead, the shock adiabat going from any initial state can be calculated. These calculations are performed for initially liquid and porous lead and bismuth.