Orbital anisotropy in a mixed-ligand system CsV₂Se₂O

Abstract We investigate the orbital anisotropy of a newly synthesized vanadium compound CsV₂Se₂O CsV 2 Se 2 O using the V L₂, ₃ L 2, 3 -edge polarization-dependent X-ray absorption spectroscopy (XAS) with the full-multiplet cluster model calculations. CsV₂Se₂O CsV 2 Se 2 O consists of two distinguishable V sites denoted ‘A’ and ‘B’ sublattices, each forming a VSe₄O₂ VSe 4 O 2 mixed-ligand octahedron. The polarization-dependent XAS exhibits anisotropic V 3 d orbital characteristics, and the corresponding linear dichroism (LD) spectrum is successfully reproduced by the model calculations under an octahedral crystal field distorted by additional ₃₄₇=0. 51 eV Δ D 4 h = 0. 51 eV tetragonal and ₃₂₇=45 meV Δ D 2 h = 45 meV orthorhombic splittings. The analysis results enable us to identify the orbital states of the A and B sublattices which are dominated by dₙ^{2-x^2} d z 2 - x 2 and dₘₙ d yz orbitals and by dₘ^{2-z^2} d y 2 - z 2 and dₙₗ d zx