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Science 11 July 1986:
Vol. 233. no. 4760, pp. 178 - 183
DOI: 10.1126/science.233.4760.178
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Articles

The Direct Methods of X-ray Crystallography

HERBERT HAUPTMAN 1

1 President and research director of the Medical Foundation of Buffalo, 73 High Street, Buffalo, NY 14203.

The electron density function rgr(r) in a crystal determines its difaction pattern, that is, both the magnitudes and phases of its x-ray diffraction maxima, and conversely. If, however, as is always the case, only magnitudes are available from the diffraction experiment, then the density function rgr(r) cannot be recovered. If one invokes prior structural knowledge, usually that the crystal is composed of discrete atoms of known atomic numbers, then the observed magnitudes are, in general, sufficient to determine the positions of the atoms, that is, the crystal structure.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ambiguities in Ab Initio Phasing.
T. O. Yeates and K. Y. J. Zhang (1993)
Science 259, 1771-1772
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