固体中稀土离子的4f^(n-1)5d组态

4f^(n-1)5d Configuration of Rare Earth Ions in Solids

简介4fn-15d电子组态研究的方法,综述近年来的研究进展,并对存在的问题进行评述。4fn-15d组态从整体来看,f电子与d电子间的Coulomb相互作用与5d电子受到的晶场作用以及4fn-1的能级劈裂为同一数量级,因此,Russell Saunders耦合和|4fn-1SLJM>-|5dΓα>耦合波函数都不能很好地反映本征态的特征。但对于某些稀土离子局部能量范围内的4fn-15d能级,HC(fd)相对较小,|4fn-1SLJM>|5dΓα>可以反映这个区域内4fn-15d能级的主要特征。光谱中是否出现精细结构,与能级的电声子耦合的强弱有关而不是与|4fn-1SLJM>-|5dΓα>耦合中|5dΓα>位置的高低有关。4fn能级与4fn-15d能级间的相互作用则与具体能级有关,不能根据个别实验就断言这种作用强或者弱。

Study on the 4fn-15d configuration is the demand of the development of various advanced materials, such as quantum cutting materials, scintillators, short wavelength laser crystals and VUV detectors. It is also an outgrowth of the rare earth theory. Since the intensity of the Coulomb interaction between felectron and delectron is comparable to the crystal field on the delectron and the interaction between the felectrons, it is incorrect to describe the 4fn15d configuration just by the 5d crystal components. Difficulty for precisely studing the 4fn-15d configuration comes from rather limited spectral data, because spectra arose from the 4fn→4fn-15d transitions are broad and of high energy, they overlap with each other, some of them being located within the conduction band of the host. Because of this difficulty, during a long period there had been only few works on the 4fn-15d configuration, even for the 4f5d, the simplest among them. The situation has been changed in recent years. New concepts and methods appeared and were applied for assigning the parameters in the calculation, choosing the basis for the wavefunctions, and getting more experimental data. Study on the 4fn-15d configuration has remarkably developed. Method for studying the 4fn-15d configuration and current progress in this area are briefly reviewed.