Estimated H-atom anisotropic displacement parameters: a comparison between different methods and with neutron diffraction results.
Estimated H-atom anisotropic displacement parameters: a comparison between different methods and with neutron diffraction results.
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估计的氢原子各向异性位移参数：不同方法和中子衍射结果之间的比较。
DOI：
10.1107/s010876730801341x
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
R. Destro
中科院分区：
文献类型：
--
作者：
P. Munshi;A. Madsen;M. Spackman;S. Larsen;R. Destro
用最近描述的三种方法对氢原子的各向异性位移参数（ADPs）进行了比较，并与中子衍射结果进行了比较。结果令人信服地表明，所有方法都能够为几个基准系统提供出色的结果，并识别出几种原子类型的系统差异。在Madsen的SHADE web服务器上，提出了一个修改和扩展的内部h原子均方位移库[J]。达成。结晶的。（2006）， 39, 757-758；http://shade.ki.ku.dk]，并且与原始的SHADE结果相比有了很大的改进，这表明它现在是三种近似程序中最容易和最广泛适用的。使用这个新的库——SHADE2——表明，与预期一致，重原子的分段刚体描述在与中子结果的一致性方面只产生了很小的改进。SHADE2库，现在被纳入到SHADE web服务器中，被推荐作为一种常规程序，用于估算h原子ADPs，适合用于分子晶体的电荷密度研究，它的广泛使用应该揭示出仍然存在的不足，也许可以克服大多数此类研究中的固有偏见。
Anisotropic displacement parameters (ADPs) are compared for H atoms estimated using three recently described procedures, both among themselves and with neutron diffraction results. The results convincingly demonstrate that all methods are capable of giving excellent results for several benchmark systems and identify systematic discrepancies for several atom types. A revised and extended library of internal H-atom mean-square displacements is presented for use with Madsen's SHADE web server [J. Appl. Cryst. (2006), 39, 757-758; http://shade.ki.ku.dk], and the improvement over the original SHADE results is substantial, suggesting that this is now the most readily and widely applicable of the three approximate procedures. Using this new library--SHADE2--it is shown that, in line with expectations, a segmented rigid-body description of the heavy atoms yields only a small improvement in the agreement with neutron results. The SHADE2 library, now incorporated in the SHADE web server, is recommended as a routine procedure for deriving estimates of H-atom ADPs suitable for use in charge-density studies on molecular crystals, and its widespread use should reveal remaining deficiencies and perhaps overcome the inherent bias in the majority of such studies.