High resolution core level photoelectron spectroscopy using He II radiation: electric field gradient splittings in group IIB and group III compounds

Abstract

Using a charged particle oscillator He II discharge lamp, we have obtained high resolution 40.8 cV photoelectron spectra of the 3d core levels of Zn and Ga in Me 2Zn and Me 3Ga respectively, and the Pb 5d core levels in Et 4Pb. The overall instrumental resolution is between 25 meV and 40 meV for all spectra. Inherent core level widths for the Zn 3d (⩽0.025 eV), Ga 3d (⩽0.15 eV) and Pb 5d (⩽0.32 eV) energy levels have been obtained from these spectra. The Me 2Zn and Me 3Ga spectra consists of five peaks due to the combined effects of spin orbit coupling and large non-cubic ligand fields (the C 0 2 term in the crystal field expansion). In contrast, the Et 4Pb 5d spectrum shows no appreciable ligand field splitting, as expected for a tetrahedral molecule.