phase problem

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phase problem

[′fāz ‚präb·ləm]
(crystallography)
The problem that arises in determining the electron density function of a crystal from x-ray diffraction data, namely that a complete determination requires knowledge of both the magnitudes and phases of the structure factors, but experimental measurements yield only the magnitudes.
References in periodicals archive ?
The period of the interfering signal that is causing the phase problem can be calculated from this display.
If one could minimize the value of this complicated expression containing thousands of variables, one could solve the phase problem.
The main purpose of the book is to introduce the reader to principles of crystallographic symmetry, to discuss some traditional, as well as modern, experimental techniques, to formulate the phase problem of crystallography, and present in some detail the methods for its indirect and direct solution which are indispensable for further work.
Part A covers the theoretical basis and such experimental techniques as principles of x-ray diffraction, solutions for the phase problem and time-resolved x-ray crystallography.