CheckCIF-GOODF01
PROC-NAME: GOODF01 Type_1/2
PURPOSE: To check that _refine_ls_goodness_of_fit_ref is within expected limits.
PROCEDURE:
TEST
(Type_2)
IF _refine_ls_goodness_of_fit_ref < 0.4 OR > 6.0 issue ALERT A
"Alert A The least squares goodness of fit parameter lies outside the range 0.40 <> 6.00"
< 0.6 OR > 4.0 issue ALERT B
"Alert B The least squares goodness of fit parameter lies outside the range 0.60 <> 4.00"
< 0.8 OR > 2.0 issue ALERT C
"Alert C The least squares goodness of fit parameter lies outside the range 0.80 <> 2.00"
Ideally, the goodness of fit (or standard deviation of an observation of unit weight) should be as close to 1.0 as possible. Values that deviate significantly from 1.0 may be an indication of one of the following: (a) the model is incorrect or incomplete or has been inadequately developed to account for disorder or solvent; (b) the reflection data are poor or weak; (c) there is twinning which has not been allowed for where overlap from the second twin domain (which may have been ignored in the data collection) causes errors in the intensities of some reflections; (d) the absorption corrections are inadequate; (e) the weighting scheme is inappropriate.
Users of SHELXL should normally obtain goodness of fit values very close to 1.0 if none of the above features is relevant. If this is not the case, check that the weighting scheme co-efficients recommended by the program have been updated immediately prior to the last refinement run. If only the weights proposed when the model was in an early stage of development are used and not subsequently updated, the goodness of fit might deviate significantly from 1.0 and the weights should be updated.
Users of other refinement software, particularly older programs or with refinement on F, might routinely obtain values for the goodness of fit in the range 1.5-2.5. This is acceptable, but authors need to be satisfied that this range for the goodness of fit is normal for good structures determined in their laboratory. However, values for the goodness of fit that are significantly smaller than 1.0 are usually a symptom of other problems with the data or model.
IF _refine_ls_goodness_of_fit_obs has been used issue a General ALERT
"_refine_ls_goodness_of_fit_obs is an old dataname which has been superceded by _refine_ls_goodness_of_fit_ref" (Type_1)
You are using an "old-fashioned", but still legal data name: _refine_ls_goodness_of_fit_obs. Please update the item to match the currently preferred name of _refine_ls_goodness_of_fit_ref. To ease this problem for the future, it is recommended that you upgrade or modify your CIF generating software accordingly.
(http://journals.iucr.org/services/cif/checking/GOODF_01.html)
目的：检查_refine_ls_goodness_of_fit_ref是否在预期范围内。
过程：
检查
(Type_2)
若_refine_ls_goodness_of_fit_ref小于0.4或大于6.0 则发布A类警告
"Alert A The least squares goodness of fit parameter lies outside the range 0.40 <> 6.00"
若_refine_ls_goodness_of_fit_ref小于0.6或大于4.0 则发布B类警告
"Alert B The least squares goodness of fit parameter lies outside the range 0.60 <> 4.00"
若_refine_ls_goodness_of_fit_ref小于0.8或大于2.0 则发布C类警告
"Alert C The least squares goodness of fit parameter lies outside the range 0.80 <> 2.00"
理想情况下，拟合优度(或称单位重量观测值的标准偏差)应尽可能接近1.0。若该值明显偏离1.0，则可能表示存在下列情形之一：(a)模型不正确或不完整，或者由于考虑到无序或溶剂而建模不完整；(b)衍射数据差或若；(c) 由于第二孪晶组分(在数据收集中可能已被忽略)的重叠引起某些衍射点的强度出现错误而导致不被允许的孪晶；(d)吸收校正不充分；(e)权重方案不合适。
若无上述情形之一，则SHELXL用户通常应获得非常接近1.0的拟合优度数值。若非如此，请检查程序建议的权重方案系数是否在上一次精修运行之前立即更新。若仅使用模型初期解析时建议的权重方案而不随后进行更新，则拟合优度可能会明显偏离1.0，应当更新权重方案。
使用其他精修软件(尤其是旧版的程序或基于F精修的程序)的用户可能通常会得到处于1.5-2.5范围的拟合优度值。这是可以接受的，但作者需要满足的是，对于实验室确定的良好结构，拟合优度的这个范围是正常的。然而，显著小于1.0的拟合优度值通常是数据或模型存在其他问题的征兆。
若使用了_refine_ls_goodness_of_fit_obs则发布一般警告
"_refine_ls_goodness_of_fit_obs is an old dataname which has been superceded by _refine_ls_goodness_of_fit_ref" (Type_1)
请更新该条目，以匹配当前首选使用的名称_refine_ls_goodness_of_fit_ref。为了将来缓解此问题，建议相应地升级或更改CIF生成软件。
警告原因：拟合优度值(GooF值或S值)超出预期范围。
解决策略：按上述蓝色文字检查数据或模型，根据具体问题进行改正，例如更新权重方案等。
