Topic
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.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, the photoelectron spectroscopy of a number of radical anions has been investigated and the following electron affinities have been found: EA(C3) = 1.981 ± 0.020 eV, EA(H2), EA(CS2) = 0.895± 0.
87 citations
TL;DR: The electronic structure of phenylalanine, tyrosine, tryptophan, and 3-methylindole in the gas phase was investigated by x-ray photoemission spectroscopy and NEXAFS, and calculations show that variations of the vertical excitation energies of different conformers are small, and cannot be resolved in the present experiment.
Abstract: The electronic structure of phenylalanine, tyrosine, tryptophan, and 3-methylindole in the gas phase was investigated by x-ray photoemission spectroscopy (XPS) and near edge x-ray absorption fine structure (NEXAFS) spectroscopy at the C, N, and O K-edges. The XPS spectra have been calculated for the four principal conformers of each amino acid, and the spectra weighted by the Boltzmann population ratios calculated from published free energies. Instead of the single peaks expected from the stoichiometry of the compounds, the N 1s core level spectra of phenylalanine and tryptophan show features indicating that more than one conformer is present. The calculations reproduce the experimental features. The C and O 1s spectra do not show evident effects due to conformational isomerism. The calculations predict that such effects are small for carbon, and for oxygen it appears that only broadening occurs. The carbon K-edge NEXAFS spectra of these aromatic amino acids are similar to the published data of the corresponding molecules in the solid state, but show more structure due to the higher resolution in the present study. The N K-edge spectra of tryptophan and 3-methylindole differ from phenylalanine and tyrosine, as the first two both contain a nitrogen atom located in a pyrrole ring. The nitrogen K-edge NEXAFS spectra of aromatic amino acids do not show any measurable effects due to conformational isomerism, in contrast to the photoemission results. Calculations support this result and show that variations of the vertical excitation energies of different conformers are small, and cannot be resolved in the present experiment. The O NEXAFS spectra of these three aromatic compounds are very similar to other, simpler amino acids, which have been studied previously.
86 citations
TL;DR: The role of reactive ion etching in obtaining oxide-to-silicon etch selectivity has been studied by combining Si etch rate and plasma optical emission spectroscopy data with results from the analysis of etched Si surfaces as mentioned in this paper.
Abstract: The role of silicon near‐surface modifications caused by reactive ion etching in obtaining oxide‐to‐silicon etch selectivity has been studied by combining Si etch rate and plasma optical emission spectroscopy data with results from the analysis of etched Si surfaces. The nature of the near‐surface modifications was established from the study of Si crystals subjected to overetching during CF4/x% H2 selective reactive ion etching of SiO2 on Si. The experimental techniques used included x‐ray photoemission spectroscopy, He ion channeling, nuclear reaction techniques, and ellipsometry. Impurity penetration has been verified by nondestructive depth profiling using nuclear reaction and angular dependent core level photoemission techniques. Fluorocarbon film deposition, a highly disordered near‐surface region (∼30 A), and etching gas related impurity penetration into the Si lattice are among the Si substrate modifications observed. By nuclear reaction analysis, hydrogen at concentrations of the order 0.1 at. % h...
86 citations
TL;DR: Using a shell model, the electron-phonon coupling is calculated and it is found that it is strong enough to give self-trapped polarons, and an efficient method for calculating ARPES spectra in undoped systems is developed.
Abstract: We present angle-resolved photoemission spectroscopy (ARPES) data on undoped La2CuO4, indicating polaronic coupling between bosons and charge carriers. Using a shell model, we calculate the electron-phonon coupling and find that it is strong enough to give self-trapped polarons. We develop an efficient method for calculating ARPES spectra in undoped systems. Using the calculated couplings, we find the width of the phonon sideband in good agreement with experiment. We analyze reasons for the observed dependence of the width on the binding energy.
86 citations
12 Apr 2011
TL;DR: In this article, a quantitative surface analysis technique that can measure elemental composition, empirical formula, chemical state and electronic state of the elements that exist within a material is presented, based on the energy of the X-ray radiation and the electron k binding energy.
Abstract: This is a quantitative surface analysis technique that can measure elemental composition, empirical formula, chemical state and electronic state of the elements that exist within a material. Narrow beams of 20 to 200 micrometers of monochromatic Al Kalpha X-rays or broad 10 to 30mm beam of non single frequencey Mg X-rays. The kinetic energy, E , of these photoelectrons is determined by the energy of the X-ray radiation, hv, and the electron k binding energy, E , as given by: b
86 citations