CRYSTALLOGRAPHIC STRUCTURES OF PbWO₄

Abstract

The crystallographic structures for PbWO₄-I (raspite), PbWO₄-II (scheelite) and PbWO₄-III (BaWO₄-II like) have been studied using the Vienna ab initio simulation package (VASP) code within the local density approximation (LDA). PbWO₄-I and PbWO₄-II were experimentally observed to coexist under normal conditions and a transformation to PbWO₄-III transition was reported to take place around 25 kbar at 600 °C. In our calculation, the raspite structure was computed to be more stable to the scheelite structure at ambient pressure with an energy difference of 25 meV/atom. At 18kbar, we calculated a transformation from the raspite to the PbWO₄-III structure, which is in reasonable agreement with the experiment.

Keywords:

• ABO4 compound
• Lead tungstate
• High pressure
• Phase transition
• Crystallographic structures
• Density of States