Evidence for [1s2p]3pshake-up channels in compounds and oxides of third-period elements

Abstract

X-ray photoemission spectra ͑XPS͒ of NaF, MgO, Al 2 O 3 , SiO 2 , InP, and NaH 2 PO 4 collected using synchrotron radiation in the 1900-3400-eV energy range are reported. Accurate XPS spectra have been collected around the Na, Mg, Al, Si, and P 1s photoemission peaks including a region extending for a few hundred eV on the high-binding-energy side. Clear features associated with additional excitations of 2p electrons, more evident in low-Z elements, have been identified. The fine structure of these satellites, dominated by the lower-upper splitting, has been studied in different compounds as a function of the photon energy. Energy positions and splitting are consistent with theoretical predictions.

Electronic and Chemical State of Aluminum from the Single- (K) and Double-Electron Excitation (KLII&III, KLI) X-ray Absorption Near-Edge Spectra of α-Alumina, Sodium Aluminate, Aqueous Al3+·(H2O)6, and Aqueous Al(OH)4–

“…For the Al KL II&III -edge spectra in Figure , these two peaks can also be ascribed to this core–hole splitting process. For α-alumina, an earlier X-ray photoelectron spectrum (XPS) clearly shows the existence of a peak due to this double electron transition at the Al-edge and a splitting of this peak with one weak and one stronger feature …”

“…For α-alumina, an earlier X-ray photoelectron spectrum (XPS) clearly shows the existence of a peak due to this double electron transition at the Al-edge and a splitting of this peak with one weak and one stronger feature. 29 Parts c and d of Figure 2 provide the same types of overlay plots for the two aqueous samples, Al 3+ and Al(OH) 4 − , that have octahedral and tetrahedral symmetry, respectively. Although the ligand symmetry about the Al atom is identical to that of α-alumina and sodium aluminate, the type of ligand is different being either H 2 O or OH − .…”

“…The existence of double-electron features in the Al K-edge spectra is similar to early reports of structure for the Si K-edge spectra of SiH 4 and other gas-phase silicon molecules . A comprehensive study of double electron excitations has been reported for the light elements of the series Si, P, S, and Cl although the existence of these features for Al has only been reported in X-ray photoelectron spectra …”

“…27 A comprehensive study 28 of double electron excitations has been reported for the light elements of the series Si, P, S, and Cl although the existence of these features for Al has only been reported in X-ray photoelectron spectra. 29 Two different theoretical approaches are used to predict features of these electronic transitions. The ΔSCF method (delta self-consistent field) was used to estimate the onsets of the K single-electron edge and the KL II&III and KL I doubleelectron edges, whereas a more complete analysis of both the K-edge position and XANES spectra was achieved using Gaussian basis restricted-excitation window time-dependent density functional theory (REW-TDDFT).…”

1sshake-up excitations in Ge andGeO2by high-energy x-ray photoemission spectroscopy

“…In addition, several compounds of third period elements were studied using a tunable synchrotron radiation source. 20 In spite of the numerous observations of background anomalies in x-ray absorption, no photoemission experiments have ever been attempted on high-energy 1s core-level excitations.…”