Valence orbitals of W(CO)₆ using electron momentum spectroscopy

The binding energy spectra and the momentum distributions of the outer valence orbitals of W(CO)₆ have been studied by using electron momentum spectroscopy as well as non-relativistic, scalar relativistic and spin-orbital relativistic DFT-B3LYP calculations. The experimental momentum profiles of the outer valence orbitals obtained with the impact energies of 1200 eV and 2400 eV were compared with various theoretical calculation results. The relativistic calculations could provide better descriptions for the experimental momentum distributions than the non-relativistic ones. Moreover, a new ordering of orbitals 10t_1u, 3t_2g, and 7e_g, i.e., 10t_1u < 3t_2g < 7e_g < 10a_1g, is established in this work.