In this work we present an interpretation of experimental O K-edge x-ray absorption near edge structure (XANES) in
perovskite-type WO3 and AWO3 compounds (A = H and Na) using three different first principles approaches: (i) fullmultiple-
scattering (FMS) formalism (the real-space FEFF code), (ii) hybrid density functional theory (DFT) method
with partial incorporation of exact Hartree-Fock exchange using formalism of the linear combination of atomic orbitals
(LCAO) as implemented in the CRYSTAL code; (iii) plane-wave DFT method using formalism of the projectoraugmented
waves (PAW) as implemented in the VASP code.