ISSN:
1434-601X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Differential cross sections and spin polarization of low-energy electrons elastically scattered by Sb4-molecules have been measured between 50 and 1000 eV from 20 to 150° and have been calculated theoretically on the basis of the independent-atom model (IAM). The interatomic distance in the Sb4-molecule is found to be 2.9±0.1 Å. In spite of its simple assumptions the IAM gives an acceptable description of the scattering at energies 〉 100 eV, except for the deep minima of the cross section and the sharp maxima of the polarization, where intramolecular plural scattering plays an important role. At energies 〈 100 eV this simple theoretical description breaks down, since here the atomic scattering amplitudes become defective and the IAM ceases to be applicable. Better results can still be obtained if a pseudopotential simulating exchange according to Yates is used in addition to the atomic potential for calculating the atomic scattering amplitudes. Despite of considerable improvement, however, the theoretical results remain unsatisfactory at 50 eV, an indication that the IAM is no longer valid. The importance of the exchange pseudopotential, which has a considerably larger range than the atomic potential, shows that at smaller energies the outer tail of the potential becomes relevant for the atomic scattering amplitudes. Then, because of the close vicinity of the atoms in the molecule, the IAM is no longer able to describe the molecular scattering correctly.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01395736
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