Backscattering of electrons in photoionization of an adsorbed CO molecule

Budau, P.; Büchner, Matthias; Raşeev, G.

doi:10.1016/0039-6028(93)90391-v

Cited by 17 publications

(8 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The quasiatomic calculations show that even a rather simple model can account for the main part of the CDAD effect from K shells, at least for relatively high photoelectron energies. Therefore, the combination of the abinitio calculations for an isolated molecule like that presented in [8] with a model description of the influence of a surface [16,19] would be a good approximation for the problem under consideration.…”

Section: Resultsmentioning

confidence: 99%

“…The existing difference between theory and experiment is connected with the neglect of the influence of the substrate as well as with the approximations made for the description of the intramolecular scattering. The use of Hartree-Fock molecular wave functions, as it was done in [4,8] together with the inclusion of the backscattering from the surface as discussed in [16], should result in much better agreement with the experiment. The curves displayed in [llJ, which showed a better agreement with the experiment, were a result of a very simple model fit taking into account only the spherical harmonics of the final state.…”

Section: Core Levels" (Co La 2o)mentioning

confidence: 92%

“…In a more realistic model, one should start from the Hartree-Fock molecular wave functions as it was done in [4,8] which include the scattering effect considered in our quasiatomic calculation. Then one should take into account also a backscattering from the surface [16] as well as nuclear degrees of freedom of adsorbed molecules such as hindered rotation and vibration [17][18][19]. Owing to hindered rotation the direction of molecular axis can strongly deviate from the surface normal which is assumed as the direction of the molecular axis in our consideration.…”

Section: A 2mjmentioning

confidence: 99%

See 2 more Smart Citations

Circular dichroism in X-ray photoemission from Pd(111) and CO/Pd(111)

Bansmann

Ostertag

Getzlaff

et al. 1995

Z Phys D - Atoms, Molecules and Clusters

View full text Add to dashboard Cite

Abstract.It is shown experimentally that in the soft X-ray region a large circular dichroism in the photoelectron angular distribution (CDAD) exists for both valence orbitals and core levels of CO molecules adsorbed on Pd(111). From theoretical consideration it follows that in the case of a spherically symmetric ground state wave function, like the lo-and 20-orbitals of CO, CDAD appears due to the lack of spherical symmetry in the final state. For carbon K-shell experimental results are compared to model calculations. Investigations at the Pd core levels proved that CDAD does also arise in X-ray photoemission from non-magnetic crystals.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Core Levels" (Co La 2o)mentioning

confidence: 92%

Section: A 2mjmentioning

confidence: 99%

See 1 more Smart Citation

Circular dichroism in X-ray photoemission from Pd(111) and CO/Pd(111)

Bansmann

Ostertag

Getzlaff

et al. 1995

Z Phys D - Atoms, Molecules and Clusters

View full text Add to dashboard Cite

show abstract

“…Budau et al discussed the appearance of CDAD due to the back-scattering of photoelectrons at the potential step between substrate and adsorbate. 6 In the present work, we will use this model to describe the energy dependence as well the angular dependence of the CDAD being observed in photoemission from the spin-orbit-split shallow core level Cs 5p.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Proof of the Back-Scattering Model for Dichroic Effects in Vuv Photoemission

et al. 2002

View full text Add to dashboard Cite

The energy dependence of the circular dichroism in the angular distribution of photoelectrons (CDAD) was investigated from the shallow Cs 5p core levels. Cesium was prepared in a hexagonal ordered monolayer on W(110). The results are mainly influenced by scattering of the photoelectrons within the adlayer. At low energies, the behavior observed is described by means of a model that treats only the back-scattering of photoelectrons at the potential step between the adlayer and the substrate. It leads to a simple method determining the position of the monolayer with respect to the substrate. In this approach, the back-scattering model is matched with the measured energy dependence of the CDAD between hν = 21 eV and hν = 33 eV. This procedure yields reliable results already for a single observation angle of the photoelectron. The distance between cesium and tungsten was determined to be (2.2 ± 0.1)Å, which corresponds to the effective distance between the center of the adsorbed layer and the potential step between the layer and the substrate. Finally, the fitted result was proven to meet the complete angular dependence of the CDAD at different photon energies.

show abstract

“…The associated calculations, of Xα [7] or ab initio types [8], considered the surface as a structureless plane, neglecting its local symmetry. In [9] calculations for a molecule fixed in space and in [10] for a linear cluster including one atom from the surface were performed with addition of the backscattering effects from a step potential representing the structureless surface.…”

Section: Introductionmentioning

confidence: 99%

Photoionization of adsorbates on sites with non-axial local symmetry. An example of the symmetry group

Kuznetsov¹,

Cherepkov²,

Raşeev³

1996

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We present an analysis of the influence of the C 4v local adsorption site symmetry on the angular distribution of photoelectrons ejected from adsorbed atoms or molecules. This analysis applies to photoelectron spectra obtained with photons of any energy in the VUV (photoelectron spectroscopy) or x-ray (XPS) regions, provided that the associated wave of the electron 'sees' the neighbouring surface atoms. The adsorbate-substrate system is modelled by a cluster of C 4v symmetry group consisting of an adsorbate and several atoms of the substrate. The analysis applies also to clean surfaces of C 4v symmetry and to molecules of the C 4v symmetry group fixed in space. This local symmetry analysis is an alternative to models of photoelectron diffraction and backscattering of photoelectrons from the surface. To unravel specific symmetry properties of the system we use the expansion of continuous spectrum wavefunctions in symmetry-adapted harmonics instead of expansion in spherical harmonics. The particular cases of circularly and linearly polarized light beams incoming along the C 4 rotation axis are considered. Terms appearing in the analytical expressions for the differential cross section and for linear or circular dichroism in the angular distribution of photoelectrons are either common to C 4v and axial symmetry groups C ∞v and D ∞h or specific to the C 4v group. The presence of the latter terms allows identification of the symmetry of the adsorption site and the position of the molecule on the surface. We illustrate the analytical expressions by modelling the CO molecule adsorbed on a Ni(100) surface.

show abstract

Backscattering of electrons in photoionization of an adsorbed CO molecule

Cited by 17 publications

References 25 publications

Circular dichroism in X-ray photoemission from Pd(111) and CO/Pd(111)

Circular dichroism in X-ray photoemission from Pd(111) and CO/Pd(111)

An Experimental Proof of the Back-Scattering Model for Dichroic Effects in Vuv Photoemission

Photoionization of adsorbates on sites with non-axial local symmetry. An example of the symmetry group

Contact Info

Product

Resources

About