Study of the Equation of State for GeO2 Glass at High Pressure

The equation of state (EOS) for non-crystalline materials (NCM) is critical to Earth and planetary science because much of the Earth is in a liquid state, such as magma and liquid iron outer core. However, accurately measuring the density of NCM at high pressure remains a challenge [1-3].
In this conference, we report 1) EOS study of GeO2 glass using an x-ray absorption method for in situ density measurement of non-crystalline materials in the diamond anvil cell and the related structural changes in polyamorphism of GeO2 glass [1,4]; 2) EOS study of GeO2 glass based on large simulation boxes of ab initio molecular dynamics (AIMD) simulations with periodic boundary conditions using different algorithms, accuracies and pseudopotentials in AIMD simulations [3,5]. We will review experimental advances in the EOS measurements of GeO2 glass, and present a detailed comparison between the experimental results and the results of the AIMD study. A reliable AIMD simulation would be necessary to explore the pressure-induced local structural changes and also very helpful to resolve the conflicting results in the local structure of GeO2 and SiO2 glasses [3].
References:
[1] X. Hong et al., RSI 78, 103905 (2007).
[2] S. Petitgirard et al., PRB 100, 214104 (2019).
[3] X. Hong et al., JPCM 35, 164001 (2023).
[4] X. Hong et al., PRB 75, 104201 (2007).
[5] K. Hong and X. Hong, Journal of Physics: Conference Series (JPCS) (accepted) (2025).