Structure of active complexes in POCl3–SnCl4–Nd3+

A comparison was made of the Stark splittings of the ⁴I_9/2, ⁴I_11/2, and ⁴F_3/2, levels of Nd³⁺ active centers in several matrices containing phosphorus. It was found that the Stark sublevels of one of the active centers in the POCl₃–SnCl₄–Nd³⁺ inorganic laser liquid were close to the neodymium sublevels in NdP₅O₁₄. Hence, the data on the structure of active complexes in NdP₅O₁₄ were used in the development of a model of the structure of type A active centers in POCl₃–SnCl₄–Nd³⁺ and in estimating the parameters of these centers.