International
Tables for
Crystallography
Volume G
Definition and exchange of crystallographic data
Edited by S. R. Hall and B. McMahon

International Tables for Crystallography (2006). Vol. G. ch. 3.4, p. 133

Section 3.4.3.1.2. Data collection

G. Madariagaa*

aDepartamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apartado 644, 48080 Bilbao, Spain
Correspondence e-mail: gotzon.madariaga@ehu.es

3.4.3.1.2. Data collection

| top | pdf |

The categories describing data collection are as follows:

DIFFRN group
DIFFRN_REFLN
DIFFRN_REFLNS
DIFFRN_STANDARD_REFLN

Categories marked with ¶ are already defined in the core CIF dictionary.

New data items in these categories are as follows:

(a) DIFFRN_REFLN [Scheme scheme7]

(b) DIFFRN_REFLNS [Scheme scheme8]

(c) DIFFRN_STANDARD_REFLN [Scheme scheme9]

The data items in these categories are straightforward extensions of the core CIF dictionary definitions to the indexing of diffraction intensities by higher-dimensional components. The _diffrn_refln_index_m_* items are the additional Miller indices [m_i] indexing the modulation wave vectors [{\bf q}_i] when the diffraction wave vector is written as [{\bf H}=h {\bf a}^{*}+k {\bf b}^{*}+ l{\bf c}^{*}+ \textstyle\sum_i m_{i} {\bf q}_{i}].

The upper limit of 8 was chosen arbitrarily to limit the number of data items defined in the msCIF dictionary.

_diffrn_reflns_limit_index_m_* items provide independent checks on the range of values recorded for each of the additional Miller indices [m_i]. _diffrn_standard_refln_index_m_* items allow the higher-dimensional Miller indices of standard reflections to be recorded.








































to end of page
to top of page