Indexing a powder diffraction pattern
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
ch. 3.4,
pp. 270-281
[ doi:10.1107/97809553602060000949 ]
d hkl values derived from the peaks in the diffraction pattern are selected and how reliable they are. Precision and accuracy in detecting peak positions are essential conditions for successful indexing (
Altomare et al., 2008 ...
Traditional indexing methods
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
Section 3.4.3.1,
pp. 273-275
[ doi:10.1107/97809553602060000949 ]
proposed by Werner (1964), then successively refined (Werner et al., 1985) and made more robust and effective (
Altomare et al., 2000, 2008, 2009). This approach, which works in the index space, was defined by Shirley as semi ...
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results from section 3.4.3 in volume H]
Examples of applications of indexing programs
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
Section 3.4.4.6,
pp. 278-280
[ doi:10.1107/97809553602060000949 ]
[
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results from section 3.4.4 in volume H]
The basic concepts of indexing
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
Section 3.4.2,
pp. 270-272
[ doi:10.1107/97809553602060000949 ]
and C, and 1 for P. S y is a factor equal to 6 for a cubic or a rhombohedral cell, 4 for a trigonal, hexagonal or tetragonal cell, 2 for an orthorhombic cell, and 1 for a monoclinic or triclinic cell.
(3) WRIP20 (
Altomare et al ...
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results from section 3.4.2 in volume H]
Introduction
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
Section 3.4.1,
pp. 270-270
[ doi:10.1107/97809553602060000949 ]
d hkl values derived from the peaks in the diffraction pattern are selected and how reliable they are. Precision and accuracy in detecting peak positions are essential conditions for successful indexing (
Altomare et al., 2008 ...
Conclusion
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
Section 3.4.5,
pp. 280-280
[ doi:10.1107/97809553602060000949 ]
Solving crystal structures using reciprocal-space methods
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
ch. 4.2,
pp. 395-413
[ doi:10.1107/97809553602060000957 ]
resolution. The peak-overlap problem also causes a significant reduction in the number of statistically independent experimental observations contained in the diffraction profile (
Altomare et al., 1995 ; David, 1999). Thus we are very far from ...
The ALLTRIALS tool in EXPO: exploring all the phase sets
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
Section 4.2.9.6,
pp. 410-410
[ doi:10.1107/97809553602060000957 ]
Å); 48% of independent observations in the pattern (
Altomare et al., 1995); 1 S, 1 N, 3 O and 12 C atoms in the asymmetric unit. Fig. 4.2.7 shows the graphical display that supports the use of ALLTRIALS. In Fig. 4.2.7 (a) the 20 ...
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results from section 4.2.9 in volume H]
Systematic decomposition
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
Section 4.2.4.3,
pp. 400-400
[ doi:10.1107/97809553602060000957 ]
of severely overlapping reflections (
Altomare et al., 2003). The clusters containing the reflections that are expected to play a minor role in DM applications, i.e. . those for which no constituent reflection falls among the largest reflections ...
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results from section 4.2.4 in volume H]
How direct methods work
Altomare, A.,
Cuocci, C.,
Moliterni, A. and
Rizzi, R.,
International Tables for Crystallography
(2019).
Vol. H,
Section 4.2.3.4,
pp. 397-399
[ doi:10.1107/97809553602060000957 ]
and are less effective that those for single-crystal data. A new figure of merit, an atom-matching-based FOM (AMB FOM), has recently been proposed (
Altomare et al., 2011 a), coupled with a special decomposition procedure (
Altomare et al., 2003 ...
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results from section 4.2.3 in volume H]
