This paper reports the present stage of commissioning of the gas-phase photoemission beamline at Elettra, Trieste. The beamline is designed for atomic and molecular science experiments with high-resolution and high-flux synchrotron radiation. It consists of an undulator source, variable-angle spherical-grating monochromator and two experimental stations. The design value of the energy range is 20 to 800 eV with a specified resolving power of over 10000. The procedure adopted for calibration of this type of monochromator is discussed. At present a resolving power up to 20000 and a range up to 900 eV have been measured. Absorption spectra taken at the argon L(II,III)-edge and at the nitrogen, oxygen and neon K-edges are as sharp as, or sharper than, any reported in the literature. The instrumental broadening is well below the natural line-width making it difficult to quantify the resolution; this problem is discussed.

No abstract

An optical layout for performing photoemission microscopy using synchrotron light from the storage ring Elettra is described. The microscope, property of the Technical University of Clausthal, was installed on an existing monochromator and the light is deflected and focused by two toroidal mirrors. A light spot of ∼30 µm diameter and a photon energy range from 45 to 160 eV has been achieved. The light illuminates the sample in the microscope at grazing incidence and chemical contrast is observed in photoemission. Apart from the standard photoemission mode of operation with synchrotron radiation, surface NEXAFS spectra from microspot areas can be measured, and an example is shown. Images can also be obtained with variable kinetic energies (and therefore variable surface sensitivity) of the secondary electrons while working in NEXAFS mode. The obliquely incident soft X‐rays cause shadows due to topography on the surface, which allows an estimate of the height of features. Three‐dimensional islands give rise to Fresnel diffraction and many fringes may be visible. This effect and its consequences for chemical imaging are discussed.