希尔什菲尔德原子精炼和从电子衍射数据的六角冰结构的动态精炼
Michał Leszek Chodkiewicz1, Barbara Olech1, Kunal Kumar Jha2
1Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, Warszawa, Warszawa 02-089, Poland.
希尔什菲尔德原子精细化 (HAR) 首次应用于电子衍射数据,由于动态散射效应,对六角冰 (Ih) 结构的影响最小. 提高准确性需要对这些动态效应进行建模.
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
- 量子化学 是一个量子化学.
背景情况:
- 在结构分析中,准确确定原子位置至关重要.
- 球形原子模型在X射线晶体学中限制了精度;在电子衍射中,不球性效应的研究较少.
- 希尔什菲尔德原子精炼 (HAR) 使用量子力学计算来准确描述电子密度.
研究的目的:
- 首次将希什菲尔德原子精细化 (HAR) 应用于动力学电子衍射数据.
- 研究HAR对六角冰 (Ih) 的结构参数的影响.
- 为了将HAR结果与独立原子模型 (IAM) 和中子衍射数据进行比较.
主要方法:
- 希尔什菲尔德原子精炼 (HAR) 的应用在动力学电子衍射数据上.
- 结果与独立原子模型 (IAM) 改进结果的比较.
- 对O-H键长度精度与参考中子衍射数据的分析.
- 通过灭绝校正和动态改进来研究动态散射效应.
主要成果:
- 在动力学改进中,HAR导致小的O-H债券长度缩短 (0.01 Å) 与IAM相比.
- 动力学改进和中子数据之间的O-H键长度差异对于HAR (0.046 Å) 比IAM (0.044 Å) 更大.
- 动态散射效应显著影响了精炼结果,动态精炼将IAM精度提高到0.021 Å.
结论:
- 虽然HAR具有电子衍射的潜力,但它的好处目前被动态散射效应所掩盖.
- 建模动态散射对于实现HAR在电子衍射中的全部潜力至关重要.
- 目前的软件限制阻止了同时进行HAR和动态改进.
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