Effects of lattice deffects on the spectral parameters of yttrium and lanthanum fluorides

Structure of X-ray photoelectron spectra of lanthanide compounds

“…Due to mixing 6 is 0.202 nm; in the LaF 8À 11 cluster, the average value over five distances R À (La7F) = 0.239 nm, and that for the other six distances, R À (La7F) = 0.272 nm. 63 of the outer and inner valence AO, as noted in a number of publications, 18,52,55,85,86 the contribution of the bonding 1a 1 IVMO prevails over the contribution of the antibonding 3a 1 IVMO, and, in total, the electrons of these MO strengthen the bond. If the contribution of the 2a 1 IVMO is taken into account, the total covalent contribution of the IVMO electrons to the chemical bond energy in the ScF 3À 6 cluster (C 3 symmetry) would be *43%.…”

“…In this case, the yttrium atom is surrounded by eight fluorine atoms located at distances R ± (Y7F) = 0.229 nm and one fluorine atom located at the distance R(Y7F) = 0.260 nm. 2,63,90 The calculation results indicate that the higher occupied OVMO are mainly formed by the F2p AO, while the lower OVMO involve the F2p and Y4d AO (see Fig. 11).…”

“…The results of nonrelativistic SCF X a DVM calculations of the electronic structures of the ScF 3À 6 (C 3 symmetry), non-symmetrical YF 6À 9 and LaF 8À 11 (D 3h symmetry) clusters (Fig. 9) 63 are given schematically in Figs 10,11,12. The structures of these clusters simulate most closely the environment of scandium, yttrium and lanthanum in ScF 3 , YF 3 and LaF 3 , respectively.…”

“…cluster (SCF Xa-DVM) in which the average value over eight bond lengths, R À (Y7F) = 0.229 nm, and for the ninth bond length, R(Y7F) = 0.260 nm. 63 The MO energies are expressed in eV (the diagram is not scaled).…”

“…The structure of the low binding energy XPS spectra of lanthanum trifluoride was interpreted using theoretical data for the electronic structures of the LaF 8À 11 cluster (D 3h symmetry) obtained by non-relativistic SCF X a -DV calculations. 5,63 The calculations were based on the crystallographic data for LaF 3 , 2, 63 which imply that five fluorine atoms in the LaF 8À 11 cluster are located at an average distance R ± (La7F) = 0.239 nm away from the lanthanum atom, while the other six fluorines are located at a distance R ± (La7F) = 0.272 nm (see Fig. 9).…”