Immiscibility between hydrogen and molten iron in planetary cores

Data from a submitted manuscript : "Immiscibility between hydrogen and molten iron in planetary cores" v1, 22 April, 2025 ---- UPDATED 13 JAN 2026 !! ---- ---- PLEASE ACCESS THE NEW VERSION OF THE DATASET !! ---- ---- UPDATED 13 JAN 2026 !! ---- Emma R. Stoutenburg 1, Razvan Caracas 2,3, Andrew J. Campbell 31 Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA2 Institut de Physique du Globe de Paris, Université Paris Cité, Paris 75005, France3 The Research Institute of the University of Bucharest (ICUB), University of Bucharest, Bucharest, Romania Corresponding author: Emma R. Stoutenburg [e-mail] This dataset containts ds01.xlsx with the following sheets: free-energy: Data derived from the thermodynamic integration and ab initio molecular dynamics simulations, including simulation details (number of iron, nFe; number of hydrogen, nH; the size of the simulation cell, acell_A (in angstroms); volume, vol_ccmol (in cm3/mol H); pressure, and temperature) as well as the thermodynamic potentials, all in kJ/mol (or kJ/molK for entropy). For simulations where we only did ab initio molecular dynamics but no thermodynamic integration, the F[mix], G[mix], S[mix] are empty. free-energy_fit: The Helmoltz free energy of mixing, volume of mixing, and internal energy of mixing from 1 to 136 GPa at 3000 K for X=0.1, 0.33, 0.5, 0.75, and 0.86, derived from fits to these parameters as a function of pressure as described in the manuscript. dome: We derive the liquid-liquid immiscibility region in the phase diagram using the data from free-energy_fit. We find Gmix(P) at 3000 K by fitting Fmix(P), Umix(P), and Vmix(P) at 3000 K (this is the data in free-energy_fit), then we assume these are constant as a function of temperature to find Gmix(P,T) = Hmix – TSmix = (Umix + PVmix) – T(Umix – Fmix)/3000 K. Then we fit these curves using the functional form described in the manuscript, find their common tangents, and contruct the immisicibility dome. Xtan_L is the hydrogen mole fraction (Fe_1-XH_X) on the left side of the common tangent (i.e. Fe-rich side) and Xtan_R is on the right (i.e. H-rich side).