| Autor: |
Ishii, Takugo, Ogasawara, Kazuyoshi, Adachi, Hirohiko, Burmester, Philipp, Huber, Günter |
| Předmět: |
|
| Zdroj: |
International Journal of Quantum Chemistry; 2004, Vol. 99 Issue 4, p488-494, 7p |
| Abstrakt: |
The authors developed a general first‐principles method for the direct calculation of multiplet structures. The method is a configuration interaction (CI) method combined with a general cluster method based on density functional theory. The present version of the method is based on a fully relativistic framework in which four‐component wave functions are handled. The calculations run independently of the semiempirical crystal field and ligand field theories, which have been the only the methods to analyze the absorption spectra involving the multiplet structures of transition metal and rare‐earth ion centers. One application of the present method is the analyses of the absorption spectra of solid‐state laser crystals. In this article, the authors focus on the multiplet structures originating from the f–f transition of Eu3+ ion in solids. In Eu3+‐doped Y2O3, the overall electronic structure is shown in agreement with the experimentally known absorption spectrum. A comparison of the multiplet structures between Eu3+ and Sm2+ ions is also shown. Although they have the same 4f6 electron configuration, the electronic structures showed different energy positions, and the tendency well agreed with that observed in experimentally known absorption spectra. In the one‐electron molecular orbital energies, the energies of Sm 4f levels were higher than those of Eu 4f levels. The difference is considered to originate from the difference in electron–nucleus attractive potential. The molecular orbitals of Eu 4f levels showed obvious mixing with O 2p orbitals, but those of Sm 4f levels did not. The calculated multiplet energies of Sm2+ were systematically smaller than those of Eu3+. The smaller multiplet energies originated from the smaller values of two‐electron integrals, indicating the relatively larger distribution of Sm 4f orbitals than those of Eu. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004 [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text