Measuring mixed-valence thorium metal-metal bonding with valence-to-core L3-edge RIXS

We recently reported the first example of thorium–thorium bonding in a crystalline cluster. Crystallography analysis and DFT results show the cluster exhibits a diamagnetic, closed-shell singlet ground state with a valence-delocalized three-thorium-two-electron σ-aromatic bond. The frontier molecular orbitals are predicted to be predominantly 6d in character, with a triplet excited state lying 0.95 eV above the ground state. We therefore propose valence-to-core RIXS studies to directly access these states with high energy resolution. To benchmark our results, measurements on a series of thorium organometallic compounds are also proposed, including classic metallocene molecules that astonishingly have yet to be studied by L3-edge RIXS.

我们近日首次报道了晶体团簇中钍-钍成键的首例案例。晶体学分析与密度泛函理论（Density Functional Theory, DFT）结果显示，该团簇具有反磁性闭壳层单重态基态，且存在价离域的三钍-两电子σ芳香键。前线分子轨道经预测主要具有6d轨道特征，其三重激发态较基态高出0.95 eV。据此，我们提议开展价芯区共振非弹性X射线散射（Resonant Inelastic X-ray Scattering, RIXS）研究，以高能量分辨率直接探测上述电子态。为基准化验证本研究结果，我们同时提议对一系列钍基有机金属化合物开展测量，其中包括经典茂金属分子——令人意外的是，这类分子此前尚未有L3边共振非弹性X射线散射的相关研究报道。