提拉法Cr：ZnWO_4晶体晶场光谱的研究

Study on Crystal-field Spectra of Cr : ZnWO_4 CrystalGrown by Czochralski Metkod

本文报道了提拉法Ｃｒ：ＺｎＷＯ＿４晶体的吸收和反射光谱。分析了ＺｎＷＯ＿４基质中Ｃｒ￣（３＋）离子的能级结构，计算了它的晶场参数，据此讨论了Ｃｒ￣（３＋）：ＺｎＷＯ＿４发射红移的机制。在空气气氛下，以提拉法生长并经退火的Ｃｒ：ＺｎＷＯ＿４晶体中，除三价Ｃｒ￣（３＋）离子以外，还可能存在少量的四价的Ｃｒ￣（４＋）离子，初步计算了它的晶场参数。

In this paper the crystal-field spectra of Cr: ZnWO_4 single erystal grown by Czochralskimethod was investigated. The crystal-field parameters of Cr￣(3+)are calculated. It isDq=1329cm￣(-1)and B=745cm￣(-1). The large emission red-shift of Crs￣(3+): ZnWO_4 isdue tothe strong polarization between the coordinative O￣(2-) of Cr￣(3+) ions and their near-neigh-bour W￣(6+) ions. It has been believed that there may be some Cr￣(4+)ions in the crystalwhich it is grown and annealed in the air atonsphere. The crystal-field parameters arealso estimated : Dq=181 4cm￣(-1), B=494cm￣(-1).