Largest Likely Values for R factors Calculated After Phase Refinement by Non-crystallographic Symmetry Averaging
- Creators
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Rees, D. C.
Abstract
The progress of phase refinement by non-crystallographic symmetry averaging is often described by the behavior of a crystallographic R factor expressing agreement between the observed structure factors and structure factors calculated from an averaged electron density map. An upper limit for this R factor is evaluated for the case of incorrectly positioned non-crystallographic symmetry operators. Depending on the degree of non-crystallographic symmetry, the upper limit on R varies from 0.29 to 0.3, for acentric structures. Incorrect structures with the correct non-crystallographic symmetry are anticipated to converge to even lower values of R. In all cases, R values calculated for incorrect structures will be significantly lower than the value of 0.586 characteristic of wrong structures lacking non-crystallographic symmetry [Wilson (1950). Acta Cryst. 3, 397-399].
Additional Information
© 1983 International Union of Crystallography. Received 22 April 1983; accepted 18 July 1983. This work was supported by a USPHS Biomedical Research Support Grant to UCLA, and a Dreyfus Foundation Starter Grant in Chemistry.Attached Files
Published - 18_rees_1983.pdf
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Additional details
- Eprint ID
- 54646
- Resolver ID
- CaltechAUTHORS:20150210-095545536
- U.S. Public Health Service (USPHS)
- Camille and Henry Dreyfus Foundation
- Created
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2015-02-11Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field