Abstract
For years Direct Methods (DM) have proven to be an invaluable tool for determining bulk crystal structures from diffraction data, and it would now appear that the same can be said for surface structures as well [1]. Surface structures can be determined from surface transmission electron (or X-ray) diffraction data by Maximum Entropy [2] or Minimum Relative Entropy [3] methods. The Minimum Entropy method is combined with a Genetic Algorithm [4,5,6] (GA) global search routine for determining possible solutions. Competition between exploration and optimization is strongly dependent upon how the GA probes the solution space, relying on factors such as mutation rate, population size, number of generated children and the form of the Figure of Merit. Atomic positions are generated using a heavy-atom holography [7] algorithm which includes minor refinement. Solutions are then discriminated based upon physical or chemical considerations, and final atomic positions refined using χ2 minimization.
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References
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© 1997 Springer Science+Business Media Dordrecht
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Landree, E., Collazo-Davila, C., Grozea, D., Bengu, E., Marks, L.D., Gilmore, C.J. (1997). Surface Structures Solved by Direct Methods. In: Dorset, D.L., Hovmöller, S., Zou, X. (eds) Electron Crystallography. NATO ASI Series, vol 347. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-8971-0_38
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DOI: https://doi.org/10.1007/978-94-015-8971-0_38
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