Optical fluorescence excitation spectra of flux-grown stoichiometric europium vanadate crystals

The intrinsic site optical absorption of EuVO₄ from ⁷F₀ to ⁵D_0, ⁵D₁, ⁵D_2, and ⁵D₃ exhibits normal behaviour, but sensitive laser excitation profiles measured in the Eu³⁺:⁷F₀ to ⁵D₀ region (580 nm) map out more than 40-50 defect lines spread over some 60 cm^-1. Each of these must be due to a distinct type of defect site in the crystal structure. A number of different EuVO₄ crystals prepared from fluxes with different compositions have been used to show that some of these point defects are associated with specific chemical impurities while others seem to be present even in the purest crystals. Electronic Zeeman shifts of the Eu³⁺:⁷F₀ to ⁵D₀ optical lines for some of the low-symmetry perturbed sites provide additional information on defect geometry and on the low-lying ⁷F₁ electronic levels for those specific perturbed sites. High degrees of site distortion are indicated for some of the sites, and principal axes are shown to make oblique angles to normal crystal axes.