PROC-NAME: WEIGH01 Type_1

PURPOSE: Check that the value of _refine_ls_weighting_scheme is recognised.

CHECKLIST:

sigma (based on measured intensity su's)

calc (calculated weights applied)

issue ALERT A if scheme isn't recognised or is set to unit weights(*).

?? "Alert A The weighting scheme doesn't match one of the standard keywords"

_refine_ls_weighting_scheme must be included in the CIF. Use one of the following keywords (do not add extra text to this field - e.g. including the weighting equation is not correct):

sigma

calc

Note that although unit weights are allowed for in the CIF dictionary, structures refined with unit weights are not acceptable.

The equation for the weighting scheme must be given under _refine_ls_weighting_details.

Example:

_refine_ls_weighting_scheme??? calc

_refine_ls_weighting_details

'w=1/[\s^2^(Fo^2^)+(0.0544P)^2^+0.1452P] where P=(Fo^2^+2Fc^2^)/3'

IF extra text is found in the field (i.e. over and above the keyword) issue an ALERT C

?? "Alert C Extra text has been found in the _refine_ls_weighting_scheme field. This should be in the _refine_ls_weighting_details field."

_refine_ls_weighting_scheme must be included in the CIF. Use one of the following keywords (do not add extra text to this field - e.g. including the weighting equation is not correct):

sigma

calc

The equation for the weighting scheme must be given under _refine_ls_weighting_details.

Example:

_refine_ls_weighting_scheme??? calc

_refine_ls_weighting_details

'w=1/[\s^2^(Fo^2^)+(0.0544P)^2^+0.1452P] where P=(Fo^2^+2Fc^2^)/3'

Note that although unit weights are allowed for in the CIF dictionary, structures refined with unit weights are not acceptable.

* Unit weights are legal in the CIF-dictionary but are not acceptable for Acta Crystallographica submissions.

(http://journals.iucr.org/services/cif/checking/WEIGH_01.html)

警告原因：_refine_ls_weighting_scheme項關(guān)鍵詞不可識別。

解決策略：一般不會出現(xiàn)，重新精修生成CIF文件。