Figure 12.2.4.1

Stubbs, M. T.; Huber, R.

doi:10.1107/97809553602060000680

International
Tables for
Crystallography
Volume F
Crystallography of biological macromolecules
Edited by M. G. Rossmann and E. Arnold

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International Tables for Crystallography (2006). Vol. F. ch. 12.2, p. 258 | 1 | 2 |

Figure 12.2.4.1

M. T. Stubbs^a ^* and R. Huber^b

^a Institut für Pharmazeutische Chemie der Philipps-Universität Marburg, Marbacher Weg 6, D-35032 Marburg, Germany, and ^bMax-Planck-Institut für Biochemie, 82152 Martinsried, Germany
Correspondence e-mail: stubbs@mailer.uni-marburg.de

Figure 12.2.4.1

The treatment of phase errors. The calculated heavy-atom structure results in a calculated value for both the phase and magnitude of $[F_{H}]$ (red). According to the value of $[\varphi_{P}]$ , the triangle $[F_{P}]$ – $[F_{H}]$ – $[F_{PH}]$ will fail to close by an amount ɛ, the lack of closure (green). This gives rise to a phase distribution which is bimodal for a single derivative. The combined probability from a series of derivatives has a most probable phase (the maximum) and a best phase (the centroid of the distribution), for which the overall phase error is minimum.