TY - JOUR
T1 - Phase diagrams, thermodynamic properties and sound velocities derived from a multiple Einstein method using vibrational densities of states
T2 - an application to MgO–SiO2
AU - Jacobs, Michael H G
AU - Schmid-Fetzer, Rainer
AU - van den Berg, Arie P.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - In a previous paper, we showed a technique that simplifies Kieffer’s lattice vibrational method by representing the vibrational density of states with multiple Einstein frequencies. Here, we show that this technique can be applied to construct a thermodynamic database that accurately represents thermodynamic properties and phase diagrams for substances in the system MgO–SiO2. We extended our technique to derive shear moduli of the relevant phases in this system in pressure–temperature space. For the construction of the database, we used recently measured calorimetric and volumetric data. We show that incorporating vibrational densities of states predicted from ab initio methods into our models enables discrimination between different experimental data sets for heat capacity. We show a general technique to optimize the number of Einstein frequencies in the VDoS, such that thermodynamic properties are affected insignificantly. This technique allows constructing clones of databases from which we demonstrate that the VDoS has a significant effect on heat capacity and entropy, and an insignificant effect on volume properties.
AB - In a previous paper, we showed a technique that simplifies Kieffer’s lattice vibrational method by representing the vibrational density of states with multiple Einstein frequencies. Here, we show that this technique can be applied to construct a thermodynamic database that accurately represents thermodynamic properties and phase diagrams for substances in the system MgO–SiO2. We extended our technique to derive shear moduli of the relevant phases in this system in pressure–temperature space. For the construction of the database, we used recently measured calorimetric and volumetric data. We show that incorporating vibrational densities of states predicted from ab initio methods into our models enables discrimination between different experimental data sets for heat capacity. We show a general technique to optimize the number of Einstein frequencies in the VDoS, such that thermodynamic properties are affected insignificantly. This technique allows constructing clones of databases from which we demonstrate that the VDoS has a significant effect on heat capacity and entropy, and an insignificant effect on volume properties.
KW - Anharmonicity
KW - Elasticity
KW - Equation of state
KW - Pressure scale
KW - Vibrational density of states
UR - http://www.scopus.com/inward/record.url?scp=84981237613&partnerID=8YFLogxK
U2 - 10.1007/s00269-016-0835-4
DO - 10.1007/s00269-016-0835-4
M3 - Article
AN - SCOPUS:84981237613
SN - 0342-1791
VL - 44
SP - 43
EP - 62
JO - Physics and Chemistry of Minerals
JF - Physics and Chemistry of Minerals
IS - 1
ER -