This is an implementation of the model presented in the paper A speciation model linking the fate of carbon and hydrogen during core – magma ocean equilibration, Earth and Planetary Science Letters (Volume 577, 1 January 2022, 117266).
https://doi.org/10.1016/j.epsl.2021.117266

This program calculates hydrogen and carbon partitioning betwenn metal and silicate melts. Enter values for carbon activity in metal (>0 and <=1), pressure in GPa, temperature in Celsius degrees, nbo/t of the silicate melt, oxygen fugacity (relative to the iron-wustite buffer), and the ppm-weight H as H2O in the silicate melt (%wt H2O/18*2*10000). Press run and the result gives you the hydrogen and carbon speciation and abundancies in the silicate melt, the carbon and hydrogen contents in the metal and the metal/silicate partitions for carbon and hydrogen. Uncertainties, if quoted by the users, are propagated through the calculations.