MAD techniques applied to powder data: finding the structure given the substructure.
The joint probability distribution function method is applied to multiple-wavelength anomalous dispersion (MAD) powder data. The distributions are calculated by assuming prior knowledge of the scattering intensities at two wavelengths and of the anomalous-scatterer substructure. The method leads to formulas estimating the full structure phases and their reliability. The procedure has been applied to two structures, one unknown and one known; the second was used as a control for the phasing procedure. In spite of the unavoidable peak overlapping in the diffraction pattern, the formulas proved to be very effective. Combined with a new algorithm for phase extension, they enabled the solution of both crystal structures.
Altomare
Angela
A
Istituto di Cristallografia, Sede di Bari, Via G. Amendola 122/o, 70126 Bari, Italy.
Burla
Maria Cristina
MC
Cuocci
Corrado
C
Giacovazzo
Carmelo
C
Gozzo
Fabia
F
Moliterni
Anna
A
Polidori
Giampiero
G
Rizzi
Rosanna
R
D018360:Crystallography, X-Ray / Q000379:methods*; D008962:Models, Theoretical; D015394:Molecular Structure; D011208:Powders / Q000737:chemistry*
D011208:Powders