Ab initiophase diagram of silver

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Silver (Ag) was traditionally viewed as a simple one-phase material.
• Recent shock-wave (SW) experiments revealed a new body-centered cubic (bcc) solid phase of silver.
• A refined phase diagram for Ag, including both face-centered cubic (fcc) and bcc phases, was proposed.

Purpose of the Study:

• To refine the Ag phase diagram using advanced computational methods.
• To accurately determine the melting curves of fcc-Ag and bcc-Ag.
• To establish the solid-solid phase transition boundary between fcc and bcc silver.

Main Methods:

• Utilized *ab initio* quantum molecular dynamics (QMD) simulations.
• Employed the Z methodology, combining direct and inverse Z methods.
• Calculated melting curves and solid-solid phase boundaries.

Main Results:

• Refined the Ag phase diagram, detailing the fcc-bcc transition.
• Obtained accurate melting curves for both fcc and bcc silver phases.
• Generated a thermal equation of state for Ag consistent with experimental data.

Conclusions:

• Silver exhibits polymorphism, possessing both fcc and bcc solid phases.
• The refined phase diagram provides a more comprehensive understanding of Ag behavior under varying conditions.
• Silver can be considered a reliable standard for shock-wave experiments due to its polymorphic nature.