EoSAlign: An Open-Source Software for Calculating, Comparing, and Aligning Pressure Under Extreme Conditions

Abstract

Accurate pressure determination is essential in high pressure experiments. Inconsistencies among pressure scales limit direct comparisons and contribute to uncertainty in measured properties, such as, phase boundaries, melting conditions, and thermodynamic models, especially above 100 GPa where existing scales diverge by >10 GPa. EoSAlign, an open-source software, can calculate, compare, and align pressures using a range of published calibrations. EoSAlign calculates pressure from experimental measurements (such as volume (A^3), Raman shift (cm^-1), or luminescence peak position (nm)) and it can be used to compare pressure values from different pressure standards. Using EoSAlign, we fit and align the bridgmanite and post-perovskite equations of state to a common scale, enabling us to reduce pressure scale related differences. EoSAlign can be applied to any high pressure data analysis to compare experimental results, improve consistency between studies, and advance our understanding of planetary interiors and high pressure physics.