Ab initio calculation of excess properties of La1-x(Ln,An)(x)PO4 solid solutions

作者：Li Yan; Kowalski Piotr M^*; Blanca Romero Ariadna; Vinograd Victor; Bo**ach Dirk

来源：Journal of Solid State Chemistry, 2014, 220: 137-141.

DOI：10.1016/j.jssc.2014.08.005

• Thermodynamics of solid solutions
• Ab initio calculations
• monazite
• Ceramic materials
• Nuclear waste management

We used ab initio computational approach to predict the excess enthalpy of mixing and the corresponding regular/subregular model parameters for La(1-x)Ln(x)PO(4) (Ln= Ce,..., Tb) and La(1-x)An(x)PO(4) (An=Pu, Am and Cm) monazite-type solid solutions. We found that the regular model interaction parameter W computed for La(1-x)Ln(x)PO(4) solid solutions matches the few existing experimental data. Within the lanthanide series W increases quadratically with the volume mismatch between LaPO4 and LnPO(4) endmembers (Delta V = V-LaPO4 - V-LnPO4), so that W(kJ/mol) = 0.618(Delta V (cm(3)/mol))(2). We demonstrate that this relationship also fits the interaction parameters computed for La(1-x)An(x)PO(4) solid solutions. This shows that lanthanides can be used as surrogates for investigation of the thermodynamic mixing properties of actinide-bearing solid solutions.

• 出版日期2014-12