These potentials have been fitted for simulations of dynamic properties of the Ge as well as the BaGe clathrate systems.
Their thermal conductivity has been calculated in http://dx.doi.org/10.1103/PhysRevB.89.214306.
D. Schopf, H. Euchner, and H.-R. Trebin
Effective potentials for simulations of the thermal conductivity of type-I semiconductor clathrate systems
Phys. Rev. B 89 (21), 214306 (2014).