Grüneisen parameter of hcp-Fe to 171 GPa

Abstract

individual gvib data points with gvib = gvib,0(V/V0) q ,a common parameterization, we found an ambient pressure gvib,0 = 2.0 ± 0.1 for the range q = 0.8 to 1.2. We also determined the Debye sound velocity (vD) from the low‐energy region of the phonon DOS and our in situ measured volumes, and used the volume dependence of vD to determine the commonly discussed Debye Gruneisen parameter (gD). Comparing our gvib(V )a ndgD(V), we found gvib to be ∼10% larger than gD at any given volume. Finally, applying our gvib(V )t o aM ie ‐Gruneisen type relationship and an approximate form of the empirical Lindemann melting criterion, we predict the vibrational thermal pressure and estimate the high‐pressure melting behavior of ‐Fe at Earth’s core pressures. Citation: Murphy, C. A., J. M. Jackson, W. Sturhahn, and B. Chen (2011), Gruneisen parameter of hcp‐Fe to 171 GPa, Geophys. Res. Lett., 38, L24306, doi:10.1029/ 2011GL049531.