Circular dichroism in core photoelectron emission from (1x1) oxygen on W(110): Experiment and theory
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Osaka Univ., (Japan). Dept. of Materials Physics
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Davis, CA (United States). Dept. of Physics
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Davis, CA (United States). Dept. of Physics; ICMM-CSIC, Madrid (Spain)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Univ. of California, Davis, CA (United States). Dept. of Physics
One of the several advantages of using synchrotron radiation is the possibility of varying it from linear polarization (LP) to left and right circular polarization (LCP and RCP), and the authors have used beamline 9.3.2 at the ALS to exploit this capability in high-resolution core-level photoelectron emission. This beamline is the only one at the ALS presently capable of varying polarization over a broad energy range from {approximately}30 to 1500 eV. In connection with core photoelectron emission from surfaces, it then becomes possible to look for circular dichroism effects in which the intensity with LCP excitation (I{sub LCP}) is not equal to the intensity with RCP excitation (I{sub RCP}). Such effects are known to occur for both non-magnetic and magnetic systems. For the latter, they constitute a novel element-specific way of studying both atomic structure and local magnetic order, but the question then arises of clearly distinguishing non-magnetic from magnetic circular dichroism effects. In order to better understand the interrelationship between non-magnetic circular dichroism and magnetic circular dichroism, the authors have performed circular dichroism measurements for the non-magnetic system of a (1x1) oxygen overlayer on W(110). This incipient-oxide overlayer corresponds to a coverage of 1 ML of oxygen, leads to a (1x12) superstructure in its LEED pattern, and exhibits W 4f core spectra that are easily resolvable into {open_quotes}oxide{close_quotes} and bulk components separated by {approximately}0.73 eV. Such non-magnetic circular dichroism in core photoelectron angular distributions (CDAD) was first observed by Schoenhense et al. from CO/Pd(111). This experiment showed that, even in what are overall non-chiral atomic geometries, circular dichroism may be present in core photoelectron emission.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 603655
- Report Number(s):
- LBNL-39981; ON: DE97007345; CNN: Contract N00014-94-0162; TRN: 98:009600
- Resource Relation:
- Related Information: Is Part Of Advanced light source: Compendium of user abstracts 1993--1996, 622 p.
- Country of Publication:
- United States
- Language:
- English
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