Beck M, Visser B, Bornhauser P, Knopp G, van Bokhoven J A, Radi P P
SwissFEL, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland.
Energy and Environment Research Division, Paul Scherrer Institute , 5232 Villigen PSI, Switzerland.
J Phys Chem A. 2017 Nov 9;121(44):8448-8452. doi: 10.1021/acs.jpca.7b09838. Epub 2017 Oct 26.
The available knowledge of the electronically excited states of the copper dimer is limited. This is common for transition metals, as the high density of states hinders both experimental assignment and computation. In this work, two-color resonant four-wave mixing spectroscopy was applied to neutral Cu in the gas phase. The method yielded accurate positions of individual rovibrational lines in the I-X and J-X electronic systems. This revealed the term symbols for the I and J states as Π (1) and Σ (0), respectively. For the Cu isotopologue, accurate molecular constants were obtained. The characterization of the J state finally allowed decisive determination of its electron configuration. The J state is obtained from the ground state by promotion of a 3dπ electron into the weakly bonding 4pπ molecular orbital. From the data analysis, lifetimes of the I state (between 10 ps and 5 ns) and J state (66 ns) were inferred.
关于铜二聚体电子激发态的现有知识有限。对于过渡金属来说，这很常见，因为态密度高会阻碍实验归属和计算。在这项工作中，双色共振四波混频光谱被应用于气相中的中性铜。该方法给出了I-X和J-X电子系统中各个振转线的精确位置。这揭示了I态和J态的光谱项符号分别为Π(1)和Σ(0)。对于铜同位素分子，获得了精确的分子常数。对J态的表征最终使得能够决定性地确定其电子构型。J态是通过将一个3dπ电子激发到弱成键的4pπ分子轨道从基态获得的。通过数据分析，推断出I态（10皮秒至5纳秒之间）和J态（66纳秒）的寿命。
