Distorted Tetrahedral CoII in K5H[CoW12O40±Õ·xH2O Probed by 2p3d Resonant Inelastic X-ray Scattering
- Boyang Liu, Ru-Pan Wang, Elliot N. Glass, Craig L. Hill, Tanja Cuk, Jun Okamoto, Di-Jing Huang, Matti M. van Schooneveld*, and Frank M. F. de Groot*
- Inorg. Chem., 2016, 55 (20), pp 10152–10160. DOI: 10.1021/acs.inorgchem.6b01228. Download
Co 2p3/2 X-ray absorption spectroscopy and high-energy-resolution (∼0.09 eV fwhm) 2p3d resonant inelastic X-ray scattering (RIXS) spectra of the single-cobalt-centered polyoxometalate K5H[CoW12O40±Õ·xH2O were measured. The low-energy dd transition features at 0.55 eV, unmeasurable with ultraviolet–visible (UV/vis) spectroscopy, were experimentally revealed in 2p3d RIXS spectra. RIXS simulations based on ligand-field multiplet theory were performed to assess the potential cobalt tetragonal symmetry distortion, which is described with the ligand-field parameters 10Dq (−0.54 eV), Ds (−0.08 eV), and Dt (0.005 eV). Because 2p3d RIXS probes not only the optical spin-allowed transitions but also the spin-forbidden transitions, we show that the current 2p3d RIXS simulation enables a series of dd feature assignments with higher accuracy than those from previous optical data. Furthermore, by wave-function decomposition analyses, we demonstrate the more realistic and detailed origins of a few lowest dd transitions using both one-electron-orbital and term-symbol descriptions.