在衍射实验中量化系统错误的两个指标:观察到的强度差异的系统错误和协议因子差距
1DataQ Intelligence, Fichtelgebirgsstrasse 66, 95448 Bayreuth, Germany.
概括
晶体衍射实验中的系统错误显著膨胀了协议因子. 不准确的标准不确定性 (s.u.) 是一个常见的问题,威胁到对小分子的数据质量评估.
科学领域:
- 晶体学 晶体学是指结晶学.
- 材料科学 材料科学 材料科学
- 数据分析 数据分析
背景情况:
- 单晶X射线和中子衍射对于确定分子结构至关重要.
- 系统错误可能会损害结构模型的准确性和数据质量.
- 权重一致系数 (wR) 是评估数据质量的关键指标.
研究的目的:
- 在衍射实验中量化系统错误对加权一致系数的影响.
- 调查公布数据集中增加的同意因子的流行率和原因.
- 突出准确标准不确定性 (s.u.) 的关键作用. 在数据评估中.
主要方法:
- 分析了314个已发表的晶体衍射数据集.
- 量化由于系统错误而增加的加权协议因数.
- 观察到的一致性因子与每个数据集的理论最小值的比较.
主要成果:
- 在50%的小分子数据集中,系统错误使权重一致系数增加了g = 3.31 (或更多) 的系数.
- 常见的系统错误包括结合,混乱和忽视结合密度.
- 没有足够的S.U. (I_obs) 被确定为一个重大,常见的系统错误.
结论:
- 标准不确定性的准确性 (s.u.) 对于可靠的数据质量评估在晶体学中至关重要.
- 没有足够准确的S.U. (I_obs) 不仅对模型参数构成威胁,而且对整个评估程序构成威胁.
- 权重协议因子的大幅增加是对已知和未知的系统错误的警告信号,包括糟糕的s.u. 估计. 估计. 这些估计.
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