Compositional dependence of spectroscopic properties of Nd3+ ions in binary calcium orthovanadates

We study the nature of the intensity parameter Ω2 and the associated line strength S of the 4I9/2 → 4G5/2 hypersensitive transition in the series of Nd3+ doped Ca9Ln(VO4)7 and Ca10A(VO4)7 double calcium orthovanadate crystals. It has been shown that the covalence of neodymium – ligand bonds has a weak effect on Ω2 and S. They are mainly determined by the symmetry of the local environment of the neodymium ions, which lowers from yttrium ion to lanthanum ion for Ca9Y/La/Nd(VO4)7 crystals and from potassium ion to lithium ion in a series of Ca10K/Li(VO4)7 crystals.