Optical spectroscopy of europium molybdate in the crystalline and amorphous States

Comparative spectroscopic studies of crystalline and amorphous samples of Eu₂(MoO₄)₃ were carried out. Amorphous samples were obtained through exposure of the β' crystal phase to a high pressure of ∼9 GPa. It was established that the transition to the amorphous state is accompanied by substantial changes both in the luminescence spectrum and the luminescence excitation spectrum. The long-wavelength absorption edge is estimated to shift by ∼0.8 eV, which is much more significant than in the case of amorphization of classical semiconductors.