稀土的一些工业应用是源于它们的特性。从镧到镥,电子在内部4f壳层上逐次填充使得稀土具有独特的光学性质。由于4f电子受外层5S~25P~6的良好屏蔽作用,它几乎与化学反应或化学变化无关,而且不易受外界影响,故在大多数情况下发射或吸收光谱是源于4f电子内层跃迁,且这种跃迁对外场的影响不敏感,这便使其有可能在利用减 Some industrial applications of rare earths are due to their characteristics. From lanthanum to acenaphthene, the successive filling of electrons on the inner 4f shell renders rare earths unique in their optical properties. Since 4f electrons are well shielded by the outer layer 5S ~ 25P ~ 6, it has almost nothing to do with chemical reactions or chemical changes and is not easily affected by the outside world. Therefore, in most cases, the emission or absorption spectra are derived from the 4f electron inner-layer transition , And this transition is insensitive to the effects of the external field, which makes it possible to use the subtraction