Finite temperature ab initio calculated thermodynamic properties of orthorhombic Cr3C2

Abstract Due to severe discrepancies between reported Gibbs energies of formation we calculate the thermodynamic properties of orthorhombic Cr3C2 ab initio in an attempt to resolve the experimental scatter. All relevant excitation mechanisms are considered, including the T=0 K formation energy, electronic entropy and quasi-harmonic and anharmonic vibrations. We find that derivative quantities of the free energy, such as isobaric heat capacity and relative thermal expansion are well described by this approach, serving as a benchmark for the calculations. Comparison shows that the final ab initio Gibbs energy has a less steep temperature dependence than what has previously been obtained by assessment.