Under Shock Compression From First Principles*

To assess the impact of oxidation on the properties of niobium subjected to shock loading, ab initio molecular dynamics (AIMD) simulations were conducted to investigate the equation of states (EOSs) of Nb₂O₅ polymorphs and explore their pressure-density relationships under shock conditions.

The Nb₂O₅ polymorphs considered in this study are the monoclinic H phase (space group P2/m), the monoclinic B phase (space group C2/c), the orthorhombic T phase (space group Pbam), and a high-pressure phase with a structure similar to the orthorhombic L-Ta₂O₅ phase (space group P2mm; referred here as L-Nb₂O₅ phase).

In particular, the present computational investigation aims at confirming whether the recently observed pressure-induced phase transition in Nb₂O₅ from the monoclinic H phase to the orthorhombic L phase near 9 GPa is an energetically favorable transformation pathway under shock loading.