Distorted Tetrahedral CoII in K5H[CoW12O40]·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; Frank M F de Groot

doi:10.1021/acs.inorgchem.6b01228

Distorted Tetrahedral Co^II in K₅H[CoW₁₂O₄₀]·xH₂O Probed by 2p3d Resonant Inelastic X-ray Scattering

Inorg Chem. 2016 Oct 17;55(20):10152-10160. doi: 10.1021/acs.inorgchem.6b01228. Epub 2016 Sep 27.

Authors

Boyang Liu¹, Ru-Pan Wang¹, Elliot N Glass², Craig L Hill², Tanja Cuk³, Jun Okamoto⁴, Di-Jing Huang⁴, Matti M van Schooneveld¹, Frank M F de Groot¹

Affiliations

¹ Inorganic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University , Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
² Department of Chemistry, Emory University , Atlanta, Georgia 30322, United States.
³ Department of Chemistry, University of California-Berkeley , 419 Latimer Hall, Berkeley, California 94720, United States.
⁴ National Synchrotron Radiation Research Center (NSRRC) , Hsinchu 30076, Taiwan.

PMID: 27673751
DOI: 10.1021/acs.inorgchem.6b01228

Abstract

The Co 2p_3/2 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]·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 10D_q (-0.54 eV), D_s (-0.08 eV), and D_t (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.