The SPOCK equation of state for condensed phases under arbitrary compression

R. Myhill

doi:10.1093/gji/ggaf082

The SPOCK equation of state for condensed phases under arbitrary compression

R. Myhill^*

^*Corresponding author for this work

School of Earth Sciences

Research output: Contribution to journal › Article (Academic Journal) › peer-review

2 Citations (Scopus)

Abstract

This short paper presents a new equation of state for condensed phases. The equation of state is built on the premise that K' , the first derivative of the bulk modulus, monotonically increases with volume according to a power law. The input parameters are the zero-pressure volume V₀, bulk modulus K₀, and first and second derivatives of the bulk modulus, K'₀ and K"₀ and also K'_∞, the value of K at infinite compression. Expressions are provided for the internal energy, pressure, and bulk modulus. The equation of state is robust for all compressions as long as K"₀ < 0 and K'_∞ < K'₀. Heuristic values are suggested for situations in which available data is not sufficient to independently constrain K"₀ and K'_∞. The equation of state compares favourably with other equations of state using recently published experimental data on Au and Pt.

Original language	English
Pages (from-to)	934-940
Number of pages	7
Journal	Geophysical Journal International
Volume	241
Issue number	2
DOIs	https://doi.org/10.1093/gji/ggaf082
Publication status	Published - 1 May 2025

Bibliographical note

Publisher Copyright:
© The Author(s) 2025. Published by Oxford University Press on behalf of The Royal Astronomical Society.

Keywords

Elasticity and anelasticity
Equations of state
High-pressure behaviour

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10.1093/gji/ggaf082Licence: CC BY

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Cite this

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abstract = "This short paper presents a new equation of state for condensed phases. The equation of state is built on the premise that K' , the first derivative of the bulk modulus, monotonically increases with volume according to a power law. The input parameters are the zero-pressure volume V0, bulk modulus K0, and first and second derivatives of the bulk modulus, K'0 and K{"}0 and also K'∞, the value of K at infinite compression. Expressions are provided for the internal energy, pressure, and bulk modulus. The equation of state is robust for all compressions as long as K{"}0 < 0 and K'∞ < K'0. Heuristic values are suggested for situations in which available data is not sufficient to independently constrain K{"}0 and K'∞. The equation of state compares favourably with other equations of state using recently published experimental data on Au and Pt.",

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author = "R. Myhill",

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N2 - This short paper presents a new equation of state for condensed phases. The equation of state is built on the premise that K' , the first derivative of the bulk modulus, monotonically increases with volume according to a power law. The input parameters are the zero-pressure volume V0, bulk modulus K0, and first and second derivatives of the bulk modulus, K'0 and K"0 and also K'∞, the value of K at infinite compression. Expressions are provided for the internal energy, pressure, and bulk modulus. The equation of state is robust for all compressions as long as K"0 < 0 and K'∞ < K'0. Heuristic values are suggested for situations in which available data is not sufficient to independently constrain K"0 and K'∞. The equation of state compares favourably with other equations of state using recently published experimental data on Au and Pt.

AB - This short paper presents a new equation of state for condensed phases. The equation of state is built on the premise that K' , the first derivative of the bulk modulus, monotonically increases with volume according to a power law. The input parameters are the zero-pressure volume V0, bulk modulus K0, and first and second derivatives of the bulk modulus, K'0 and K"0 and also K'∞, the value of K at infinite compression. Expressions are provided for the internal energy, pressure, and bulk modulus. The equation of state is robust for all compressions as long as K"0 < 0 and K'∞ < K'0. Heuristic values are suggested for situations in which available data is not sufficient to independently constrain K"0 and K'∞. The equation of state compares favourably with other equations of state using recently published experimental data on Au and Pt.

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