Electronic structure of lanthanide dimers |
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| Authors: | XIAOYAN CAO MICHAEL DOLG |
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| Institution: | 1. Institut für Theoretische Chemie, Universit?t zu K?ln , D-50939, Germany;2. Biochemistry Department , Zhongshan University , Guangzhou, 510275, PR, China;3. Institut für Theoretische Chemie, Universit?t zu K?ln , D-50939, Germany |
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| Abstract: | Relativistic energy-consistent small-core lanthanide pseudopotentials of the Stuttgart-Bonn variety and extended valence basis sets have been used for the investigation of some selected lanthanide dimers with open 4f shell, that is Ce2, Pr2 and Gd2. Comparison is made with results of corresponding previous studies of La2 and Lu2 as well as to available experimental data. The trends in the molecular constants of the dimers of the lanthanide series are discussed. The ground state candidates of Ce2(4f14f1σ2 gπ4 u 1Σ+ g, 1Σ? u, 3Σ? g, 3Σ+ u, 16g, 36u) and Pr2(4f24f2σ2 gπ4 u 5Σ+ g, 5Σ? u, 510g) are degenerate within 20cm?1 and have the same valence subconfiguration σ2 g π4 u, which was previously found to give rise to the La2(4f04f0σ2 gπ4 u 1Σ+ g) ground state. In the case of Gd2 the 4f74f7σ2 gσ1 uσ2 u; 19Σ? g ground state found previously is confirmed. The derived molecular constants are the best theoretical estimates available at present and show a satisfactory agreement with experimental data. Discrepancies in the vibrational constants of La2, Ce2 and Pr2 are shown to be probably related to quite large Ar-matrix shifts. |
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