R.T. Poole

Electronegativity as a unifying concept in the determination of Fermi energies and photoelectric thresholds

Abstract The method proposed by Nethercot for the determination of the Fermi energies and photoelectric thresholds of simple binary compounds has been successfully applied to some AB 2 compounds and metals.

The electronic structure of the valence bands of solid NH3 and H2O studied by ultraviolet photoelectron spectroscopy

Abstract The results of a photoelectron study using ultraviolet 40.81 eV photons (UPS) of the outermost bands of the molecular solids NH 3 and H 2 O are reported. The binding energies, the energy separation, the band widths and the branching ratio of the two outermost bands of solid NH 3 are found not to be significantly different from the 3a l and 1e molecular orbital states of the gaseous NH 3 UPS spectrum. This implies that hydrogen bonding has not produced any significant change in the electronic structure of the valence bands of solid NH 3 . Because of a much smaller intermolecular hydrogen bond length in solid H 2 O compared to that in solid NH 3 , the hydrogen bond does, however, produce a significant change in the valence bands of H 2 O on solidification, and because of the orbital geometry it predominantly affects the 3a l molecular orbital state.

A semi-empirical determination of the Alkali metal conduction band relaxation energies during photoelectron emission

Abstract Using a semi-empirical method the alkali metal conduction band relaxation energies are determined to ca. 0.1 eV. Comparison with theoretical values given by Ley et al. shows that the localized hole model is superior to the nonlocalized hole model.

On the relationship between the chemical bond energy and the electron energy levels of strongly ionic compounds

Abstract The analysis of experimental data suggests that the energy levels of ions in a crystal shift rigidly by an amount equal to the Madelung energy (electrostatic bond energy) maintaining the same separation as in the free ion. This leads to the conclusion that the electrostatic bonding energies of ions in a crystal is taken up partly by the orbital electrons and partly by the nuclear charge.

Electronic structure of the valence bands of SnF2 studied by ultraviolet photoelectron spectroscopy

Abstract The main features of the photoelectron spectrum of the valence bands of solid-phase SnF2 are susccessfully interpreted in terms of linear combination of atomic orbitals-molecular orbital theory.

The valence band relaxation energies of silicon and germanium during photoelectron emission

Abstract The valence band relaxation energies of the intrinsic semiconductors silicon and germanium are estimated using a classical and a quantum-mechanical method and are found to be similar in magnitude to values reported for conductors and insulators. It is shown that the XPS electronic valence band structures of Si and Ge reflect the cohesive energies when the binding energies are corrected for relaxation effects.

Crystal-field splitting in strongly ionic solids studied by photoelectron spectroscopy

The splittings of the outermost 4d, 5d and 5p bands of some strongly ionic solids have been measured using 40.81 eV ultraviolet photoelectron spectroscopy. The level splitting of the solids with initial state metal ion configurations of 4d10 and 5p6 are interpreted in terms of crystal field effects on the final state 4d9 and 5p5 ions respectively. The level splitting for solids with an initial state metal ion configuration of 5d10 6s2 are found to agree with the free ion spin-orbit splitting and this is attributed to the screening of the crystal-field symmetry by the outer two 6s electrons.