Variable photon energy photoelectron spectroscopy on FeCl4-. An unusual electronic structure for high-spin d5 complexes

Photoelectron spectroscopy of MoS2 at the sulfur 2p absorption edge

“…The electron excited to the Mo-based antibonding level acts as a spectator in the decay procei.s. Shake-up enhancement is also observed at the S and Si 2p edges in SF 6 and SiF 4 , compounds 17 " 2 0 in which the excited central atom should be electron deficient relative to S in MoS 2 , decreasing the effective Coulomb repulsion. Alternatively, enhancement of both F-based abonding main-band features and shake-up satellites occurs after excitation of a B Is electron in BF 3 .…”

“…6 Such a picture is difficult to describe for the S 2p edge of MoS 2 , where the atomic transitions must be viewed as occurring from the S 2p core level to the S 3p valence levels. However, atomic selection rules and the formally filled 3p 6 subshell of the sulfide ion preclude these transitions. These transitions should be discussed using the MO electronic configurations as written in Eqs.…”

“…This process can be demonstrated more simply in an atomic picture: excitation S (2p)6... S (3p)6 Mo (4d) 2 -_ S (2p) 5 ... S (3p) 6 Mo (4d) 3 (3a)…”

“…13, 14 Some work has been performed on nonmetal 2p soft X-ray absorption edges, Including ýwo reports of the S L 2 3 edge in MoS 2 . 1 5 , 6 A limited number of resonant PES studles have been reported at nonmeti edges, 17 " 2 1 but no reports of nonmetal edge resonances in transition metal compounds have been made. PES studies performed on gas-phase compounds such as SIF& 18,19 and SF 6 2 0 have shown enhancement of shake-up satellites rather than mainband feature at the Si and S 2 p edges, respectively.…”

“…1 5 , 6 A limited number of resonant PES studles have been reported at nonmeti edges, 17 " 2 1 but no reports of nonmetal edge resonances in transition metal compounds have been made. PES studies performed on gas-phase compounds such as SIF& 18,19 and SF 6 2 0 have shown enhancement of shake-up satellites rather than mainband feature at the Si and S 2 p edges, respectively. Alternatively, resonant PES of BF 3 showed S~21 enhancement of main-band features as well as shake-ups at the B Is edge.…”