Experimental observation of circular dichroism in photoemission
1990; Elsevier BV; Volume: 41; Issue: 1-3 Linguagem: Inglês
10.1016/0042-207x(90)90281-3
ISSN1879-2715
AutoresC. Westphal, Joachim Bansmann, M. Getzlaff, G. Schönhense,
Tópico(s)Electron and X-Ray Spectroscopy Techniques
ResumoA new phenomenon in photoemission from adsorbates is reported. With circularly polarized synchrotron radiation and a special observation geometry (defining a ‘handedness’ of the directions of photon impact, electron ejection and surface normal) photoemission intensity asymmetries arise upon reversal of photon helicity. Circular Dichroism in the Angular Distribution of photoelectrons (CDAD) has been theoretically predicted in the pure electric dipole approximation. The phenomenon should occur for all molecular adsorbates which are spatially oriented. First experimental results for a diatomic molecule (CO), a polyatomic molecule (benzene) and a molecule with significant spin-orbit interaction (CH 3 l) revealed CDAD asymmetries in all the photoemission signals corresponding to the various molecular orbitals.
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