Study of the Excited States of the Lnner Core Levels in Rare-Earth Compounds

稀土化合物内核能级激发态的研究

• 批准号: 60540214
• 负责人: AITA Osamu
• 金额: $ 0.96万
• 依托单位: College of Engineering, University of Osaka Prefecture
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60540214/
• 关键词: Resonant emission; Valence fluctuation; 等色X線

The electronic property of rare-earth compounds containing a partially filled 4f shell has been a subject of theoretical and experimental studies because the rare-earth ions in some of these substances are in a homogeneous mixed-valence state. In the present study we measured the rare-earth <M_(4,5)> emission spectra of some rare-earth hexaborides( <CeB_6> , <NdB_6> , and <SmB_6> ) with near-thrshold electron excitation method to elucidate the electronic structure of these substances. The characteristic isochromat spectra and the continuum limit spectra were also measured for this purpose. The results are summarized as follows:1. The positions of the peaks in the rare-earth <M_(4.5)> emission spectra of these substances clearly coincide with those of the absorption peaks. Therefore, the emission peaks are interpreted as the resonant emissions caused by the transition 3 <d^9> 4 <f^(n+1)> 3 <d^(10)> 4 <f^n> , where n equals the number of the 4f electrons in the ground state. The Sm <M_(4 … More ,5)> emission and characteristic isochromat spectra of Sm <B_6> show no distinct indication of the spectrum corresponding to the <Sm^(2+)> ion regardless of the valence mixing of this substance. 2. The characteristic isochromat spectra at the photon energy of the resonant peak exhibit that the electron-beam energy beyond the energy of the resonant peak is required for the generation of the resonant emission(3 <d^9> 4 <f(n+1)> 3 <d^(10)> 4 <f^n> ). This is ascribed to the formation of the transient state 3 <d^9> 4 <f^(n+2)> , which is caused by both the electron excited from the 3d level and the incident electron losing the initial energy. 3. The rare-earth <N_(4,5)> absorption spectra of some rare-earth compounds were also measured. The Sm <N_(4,5)> absorption spectrum of Sm <B_6> shows no distinct indication due to the <Sm^(2+)> ion. The absorption structure corresponding to the <Sm^(2+)> ion may be smeared owing to the autoionization process of the excited state 4 <d^9> 4 <f^7> of the <Sm^(2+)> ion because this state is located above the 4d ionization threshold of the <Sm^(2+)> ion. Less

含有部分填充的 4f 壳层的稀土化合物的电子性质一直是理论和实验研究的主题，因为其中一些物质中的稀土离子处于均匀的混合价态。在本研究中，我们采用近阈值电子激发方法测量了一些稀土六硼化物（<CeB_6>、<NdB_6>和<SmB_6>）的稀土<M_(4,5)>发射光谱，以阐明这些物质的电子结构。为此目的还测量了特征等色光谱和连续极限光谱。研究结果如下： 1．这些物质的稀土<M_(4.5)>发射光谱中的峰位置与吸收峰的位置明显一致。因此，发射峰被解释为由跃迁引起的共振发射 3 <d^9> 4 <f^(n+1)> 3 <d^(10)> 4 <f^n> ，其中 n 等于基态 4f 电子的数量。 Sm <M_(4 … More ,5)> 发射光谱和 Sm <B_6> 的特征等色光谱没有显示出与 <Sm^(2+)> 离子对应的光谱的明显指示，无论该物质的价态混合如何。 2. 共振峰光子能量处的特征等色谱表明，产生共振发射需要超过共振峰能量的电子束能量(3 <d^9> 4 <f(n+1)> 3 <d^(10)> 4 <f^n> )。这归因于瞬态 3 <d^9> 4 <f^(n+2)> 的形成，这是由从 3d 能级激发的电子和入射电子失去初始能量引起的。 3.还测量了一些稀土化合物的稀土<N_(4,5)>吸收光谱。 Sm <B_6> 的 Sm <N_(4,5)> 吸收光谱由于 <Sm^(2+)> 离子而没有显示出明显的迹象。由于 <Sm^(2+)> 离子的激发态 4 <d^9> 4 <f^7> 的自电离过程，对应于 <Sm^(2+)> 离子的吸收结构可能会被涂抹，因为该状态位于 <Sm^(2+)> 离子的 4d 电离阈值之上。较少的

项目成果

Osamu Aita et al: "Rare-Earth <N_(4,5)> Absorption Spectra of Some Rare-Earth Compounds" Journal of the Physical Society of Japan. 53. 649-654 (1987)

Osamu Aita 等人：“某些稀土化合物的稀土 <N_(4,5)> 吸收光谱”日本物理学会杂志。

Osamu Aita et al: "Sm <M_(4,5)> emission spectra of Sm metal and Sm <B_6> with fluorescence excitation and near-threshold excitation methods" Physical Review B. 34. 8230-8236 (1986)

Osamu Aita 等人：“采用荧光激发和近阈值激发方法的 Sm 金属和 Sm <B_6> 的 Sm <M_(4,5)> 发射光谱” 物理评论 B. 34. 8230-8236 (1986)

Osamu Aita: Journal of the Physical Society of Japan. 53. 649-654 (1987)

Osamu Aita：日本物理学会杂志。

Osamu Aita: Physical Review B. 34. 8230-8236 (1986)

Osamu Aita：物理评论 B.34.8230-8236 (1986)