Department of Chemistry, National University of Ireland, Maynooth, County Kildare, Ireland.
J Chem Phys. 2011 Mar 28;134(12):124501. doi: 10.1063/1.3564947.
Absorption spectroscopy recorded for annealed samples of matrix-isolated atomic europium reveals a pair of thermally stable sites in Ar and Kr while a single site exists in Xe. Plots of the matrix shifts of the visible s → p bands versus host polarizability, allowed the association of the single site in Xe and the blue sites in Ar and Kr. On the basis of the similar ground state bond lengths expected for the Eu-rare gas (RG) diatomics and the known Na-RG molecules, the blue sites are attributed to Eu occupancy in the smaller tetra-vacancy while the red sites are proposed to arise from hexa-vacancy sites. Both sites are of cubic symmetry, consistent with the pronounced Jahn-Teller structure present on the y(8)P ← a(8)S(7/2) transition for these bands in the three hosts studied. Site-selective excitation spectroscopy has been used to reanalyze complex absorption spectra previously published by Jakob et al. [Phys. Lett. A 57, 67 (1976)] for the near-UV f → d transitions. On the basis that a pair of thermally stable sites exist in solid argon, the occurrence of crystal field splitting has been identified to occur for the J ≥ 5/2 level of the (8)P state when isolated in these two sites with cubic symmetry. From a detailed lineshape analysis, the magnitude of the crystal field splittings on the J = 5/2 level in Ar is found to be 105 and 123 cm(-1) for the red and blue sites, respectively.
退火的基质隔离原子铕样品的吸收光谱显示，在 Ar 和 Kr 中存在一对热稳定的位点，而在 Xe 中存在单个位点。可见 s → p 带的基质位移与主极化率的关系图，将 Xe 中的单个位点与 Ar 和 Kr 中的蓝点联系起来。基于 Eu-稀有气体（RG）双原子和已知的 Na-RG 分子的预期基态键长相似，蓝点归因于 Eu 在较小的四面体空位中的占据，而红点则被认为来自六面体空位。这两个位点都是立方对称的，与研究的三种基质中这些带的 y(8)P ← a(8)S(7/2)跃迁上存在的明显 Jahn-Teller 结构一致。选择激发光谱技术已被用于重新分析 Jakob 等人先前发表的复杂吸收光谱[Phys. Lett. A 57, 67 (1976)]，用于近紫外 f → d 跃迁。基于固体氩中存在一对热稳定的位点，当在具有立方对称性的这两个位点中隔离时，（8）P 态的 J ≥ 5/2 能级的晶体场分裂已被确定发生。通过详细的线宽分析，发现 Ar 中红、蓝点上 J = 5/2 能级的晶体场分裂分别为 105 和 123 cm(-1)。
