Photoemission spectroscopy

About: Photoemission spectroscopy is a research topic. Over the lifetime, 10821 publications have been published within this topic receiving 250888 citations. The topic is also known as: photoelectron spectroscopy & PES.

Ultrafast soft X-ray photoelectron spectroscopy at liquid water microjets.

Abstract: Since the pioneering work of Kai Siegbahn, electron spectroscopy for chemical analysis (ESCA) has been developed into an indispensable analytical technique for surface science. The value of this powerful method of photoelectron spectroscopy (PES, also termed photoemission spectroscopy) and Siegbahn’s contributions were recognized in the 1981 Nobel Prize in Physics.The need for high vacuum, however, originally prohibited PES of volatile liquids, and only allowed for investigation of low-vapor-pressure molecules attached to a surface (or close to a surface) or liquid films of low volatility. Only with the invention of liquid beams of volatile liquids compatible with high-vacuum conditions was PES from liquid surfaces under vacuum made feasible. Because of the ubiquity of water interfaces in nature, the liquid water–vacuum interface became a most attractive research topic, particularly over the past 10 years. PES studies of these important aqueous interfaces remained significantly challenging because of the ...

X-ray photoemission spectroscopy study of hexavalent uranium compounds

Abstract: The electronic structure of the outer occupied levels of a series of hexavalent uranium (predominately uranyl) compounds was studied using x-ray photoemission spectroscopy (XPS). The changes in the spectral features of the outer occupied levels with the variation of the uranium-oxygen bond lengths (1.7-- 2.1 A) are systematically investigated. Previously unexplained spectral structure has been found to result from ligand-field splitting of the occupied U $sup 6$p$sub 3$/$sub 2$ levels. The XPS results are compared with predictions of a relativistic molecular-cluster calculation and with the results of a simple point-charge crystal-field model. When the crystalline electric fields generated by both the primary and secondary ligands are taken into consideration, excellent quantitative agreement is obtained between the XPS data and the molecular-cluster results with no parameter adjustment. (AIP)

Fermi-liquid line shapes measured by angle-resolved photoemission spectroscopy on 1-T-TiTe2.

Abstract: We have performed high-resolution angle-resolved photoemission spectroscopy (ARPES) on the layered compound 1-T-${\mathrm{TiTe}}_{2}$, whose low-energy properties are those of a normal metal, and analyzed the experimental line shapes in terms of the Fermi-liquid self-energy. We find excellent agreement between the measured and theoretical spectral weight distribution, while line profiles expected for other theoretical models such as the marginal Fermi liquid clearly fail to reproduce the experimental spectra. This demonstrates that ARPES line shapes are able to reflect the nature of an interacting electron system.

Superconducting Gap and Pseudogap in Iron-Based Layered Superconductor La(O1-xFx)FeAs

Abstract: We report high-resolution photoemission spectroscopy of newly-discovered iron-based layered superconductor La(O 0.93 F 0.07 )FeAs ( T c = 24 K). We found that the superconducting gap shows a marked deviation from the isotropic s -wave symmetry. The estimated gap size at 5 K is 3.6 meV in the s - or axial p -wave case, while it is 4.1 meV in the polar p - or d -wave case. We also found a pseudogap of 15–20 meV above T c , which is gradually filled-in with increasing temperature and closes at temperature far above T c similarly to copper-oxide high-temperature superconductors.