Thermodynamic properties of rhodium at high temperature and pressure by using mean field potential approach

• Published in: The European physical journal. B, Condensed matter physics Condensed matter physics, 2016-10, Vol.89 (10), p.1-8, Article 219
• Main Authors: Kumar, Priyank, Bhatt, Nisarg K., Vyas, Pulastya R., Gohel, Vinod B.
• Format: Article
• Language: English
• Subjects: Analysis; Anharmonicity; Complex Systems; Computation; Condensed Matter Physics; Electronic structure; Electrons; Enthalpy; Equations of state; Extreme environments; Fluid- and Aerodynamics; Fluorides; Free energy; Gruneisen parameter; High temperature; Lattice vibration; Melt temperature; Physics; Physics and Astronomy; Platinum group compounds; Regular Article; Rhodium; Solid State Physics; Thermal expansion; Thermodynamic properties; Thermodynamics; Thermophysical properties; Transition metals
• ISSN: 1434-6028; 1434-6036
• DOI: 10.1140/epjb/e2016-70367-0

The thermophysical properties of rhodium are studied up to melting temperature by incorporating anharmonic effects due to lattice ions and thermally excited electrons. In order to account anharmonic effects due to lattice vibrations, we have employed mean field potential (MFP) approach and for thermally excited electrons Mermin functional. The local form of the pseudopotential with only one effective adjustable parameter r c is used to construct MFP and hence vibrational free energy due to ions – F ion . We have studied equation of state at 300 K and further, to access the applicability of present conjunction scheme, we have also estimated shock-Hugoniot and temperature along principle Hugoniot. We have carried out the study of temperature variation of several thermophysical properties like thermal expansion ( β P ), enthalpy ( E H ), specific heats at constant pressure and volume ( C P and C V ), specific heats due to lattice ions and thermally excited electrons ( C V ion and C V el , isothermal and adiabatic bulk moduli ( B T and B s ) and thermodynamic Gruneisen parameter ( γ th ) in order to examine the inclusion of anharmonic effects in the present study. The computed results are compared with available experimental results measured by using different methods and previously obtained theoretical results using different theoretical philosophy. Our computed results are in good agreement with experimental findings and for some physical quantities better or comparable with other theoretical results. We conclude that local form of the pseudopotential used accounts s - p - d hybridization properly and found to be transferable at extreme environment without changing the values of the parameter. Thus, even the behavior of transition metals having complexity in electronic structure can be well understood with local pseudopotential without any modification in the potential at extreme environment. Looking to the success of present scheme (MFP + pseudopotential) we would like to extend it further for the study of liquid state properties as well as thermophysical properties of d and f block metals.