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SAPI Direct Methods for Small Structures and Superstructures

  • Operating system: Windows95, 98, NT, 2000 and XP
  • The name SAPI is an abbreviation of "Structure Analysis Programs with Intelligent control". It may also be read inversely as "Institute of Physics, Academia Sinica".
  • SAPI is written in Fortran for crystallographic computation and C++ for graphic operation.
  • SAPI is based on Multan and differs from it mainly by the ability of resolving phase ambiguities due to pseudo symmetry.
  • Features:
    • The program can automatically handle diffraction data from structures having pseudo-translational symmetry and lead directly to the correct solution in favorable cases. This is particularly useful for solving superstructures without relying on an assumed structure model.
    • The program can recognize pseudo-centrosymmetric solutions when dealing with non-centrosymmetric structures. In addition, the program can break the enantiomorphous ambiguity given the "atomic positions" of both enantiomorphs.
    • The program possesses the ability of intelligent control on the path of phase development according to the feature and complexity of the structure.
    • The program enables combination of Patterson and direct methods. Besides, subroutines are provided for automatic Patterson analysis of heavy-atom containing structures.
    • Sophisticated graphic interface is provided for data preparation, program control and for displaying and manipulating output results.
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