Simulation of Simple and Complex Gadolinium Molybdates by the Interatomic Potential Method

Crystals of ferroelectric‒ferroelastic gadolinium molybdate Gd 2 (MoO 4 ) 3 , calcium molybdate CaMoO 4 , and double sodium‒gadolinium molybdates of stoichiometric (Na 1/2 Gd 1/2 MoO 4 ) and cationdeficient (Na 2/7 Gd 4/7 MoO 4 ) compositions, which are used to design solid-state lasers, phosphors, and white LEDs, have been simulated by the interatomic potential method. Their structural, mechanical, and thermodynamic properties are calculated using a unified system of interatomic potentials and effective ion charges, which demonstrated transferability and made it possible not only to describe the existing experimental data but also to predict some important physical and thermodynamic properties of molybdate crystals. The influence of the deviation from stoichiometry and partial ordering of cations on sites in nonstoichiometric crystals on the properties and local structure of sodium‒gadolinium molybdates is discussed.