On the computational complexity of determining polyatomic structures by X-rays
β Scribed by R.J. Gardner; P. Gritzmann; D. Prangenberg
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 297 KB
- Volume
- 233
- Category
- Article
- ISSN
- 0304-3975
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β¦ Synopsis
The problem of recovering the structure of crystalline materials from their discrete X-rays is of fundamental interest in many practical applications. An important special case concerns determining the position of atoms of several di erent types in the integer lattice, given the number of each type lying on each line parallel to some lattice directions. We show that the corresponding consistency problem is NP-complete for any two (or more) di erent (ΓΏxed) directions when six (or more) types of atoms are involved.
π SIMILAR VOLUMES
The fine structure of the K-absorption edges of germanium and arsenic, respectively present in the vapours GeCl~ and AsCla, has been determined. In both cases this fine structure is very pronounced and extends to a distance of several hundred volts from the edge. For GeCl, the fine structure is in