La 3d Research Articles

Muon Knight shift investigations in LaAg1-xInx

Muon Knight shift measurements are performed in the pseudobinary intermetallic compound LaAg1-xInx (CsCl structure). Negative, temperature-dependent Knight shift values are found. This observation is discussed in terms of a negative transferred hyperfine field between the La 5d states and the muon, whose magnitude varies from -3 kG mu B-1 to -10 kG mu B-1 for 0<or=x<or=0.3.

XPS core level and valence band spectra of LaH 3

Abstract XPS analysis of LaH3 shows that the conduction band of the La metal disappears and that a new hydrogen induced band is formed 5.8 eV below EF. The La 3d core levels of LaH3 are split into two peaks with about 1 3 of the intensity being in the low binding energy peak. We propose to describe the observed 3d structure by the screening of the 3d hole by means of a charge transfer from the new hydrogen band to the empty 4f level, the latter being pulled down below the hydrogen band. This would be a shake down process as in La metal.

Delayed onset of 4d photoemission relative to the giant 4d photoabsorption of La

Abstract For the giant 4d photoabsorption of La, both the total photoabsorption spectrum and the N4.5-derived Auger emission intensity spectrum increase significantly above hν ≅ 112 eV, with spectral peaks at hν = 118 and 119 eV, respectively. However, the predominant 4d photoemission partial cross section shows a delayed onset of ∼ 4 eV, with a peak at hν = 121 eV, while the 5s, 5p, and 5d partial cross sections all show a strong resonant enhancement at lower energies, with spectral peaks at hν = 116.6 eV. These results are compared with a recent many-body calculation for Ce. The photon energy dependence of the La 4d 5 2 /4d 3 2 photo-emission branching ratio is consistent with a “final-state model.”

The multicomponent structure of the 4d orbital in X-ray photoelectron spectra of the lanthanum(III) ion

Abstract The detailed structure of La (4d) X-ray photoelectron spectra in lanthanum oxide and chromites have been resolved. The energy separations between the satellites and the main peaks are the same for both the 4d and 3d orbitals, and therefore the 4d does not differ from the 3d because of a higher covalency. The multielectron charge transfer processes occur in both cases and for the chromites as well as for the lanthanum oxide. However, the separation is smaller for the chromites.

Shake-up satellites in x-ray photoelectron (ESCA) spectra of 5f 0 Th(IV) compounds

Abstract X-ray photoelectron (ESCA) spectra of the Th 4f levels have been recorded in 12 Th compounds. Weak satellites are observed in all the 4f spectra at binding energies 4–6 eV from the primary photolines. On the basis of a multiple scattering calculation in ThO2, these satellites are assigned to ligand (e.g. O 2p) to Th 5f shake-up transitions. As with La 3d satellites, the satellite intensities correlate well with the nephelauxetic order of ligands.

XPS valence bands of La, Ce and Gd and their aluminium alloys

The XPS valence band spectra of La, Ce and Gd metal and of their aluminium alloys show the 5d band in La metal at 0.8 eV below the Fermi energy with a width of about 1.5 eV; in Ce and 4f band and 5d band are at 0.5 eV and 1.7 eV below the Fermi energy with widths of 0.7 eV and 1.5 eV respectively. The Gd 5d band is very similar to the La 5d band, while the 4f level is well localized at 8.0 eV below the Fermi energy.