氢键准则在DMSO水溶液中应用的评价

利用分子动力学模拟方法, 分别采用几何准则和能量准则分析了不同浓度下的二甲基亚砜(DMSO)水溶液的氢键统计和动力学等特性. 结果显示, 两种氢键准则可以很好地反映出溶液的氢键性质随浓度的变化趋势. 通过分析比较发现, 由于几何准则不能有效地排除具有弱对势能的分子对, 因此其统计的氢键数量要大于能量准则的结果.此外, 能量准则对于分子间相对取向的区分存在不足, 进而引起氢键寿命的计算结果偏大.因此,为使氢键分析更加准确, 本文建议使用几何-能量混合型氢键准则.

Evaluation of the Application of Hydrogen Bonding Criteria to DMSO Aqueous Solution

Geometric and energetic criteria have been used to analyze the hydrogen bonding statistics and dynamics of aqueous solutions of dimethylsulfoxide (DMSO) of different concentrations using molecular dynamics simulation. These two hydrogen bonding criteria both reproduced the changes of the hydrogen bonding properties of the solutions with increasing concentration. Comparison of the results obtained using the two criteria revealed that the geometric criterion cannot exclude pairs that have weak pair interaction energy. As a result, the number of hydrogen bonds determined by the geometric criterion is larger than that by the energetic criterion. The energetic criterion has less ability to distinguish pairs that have improper relative orientation compared with the geometric criterion. However, the number of deficient hydrogen bonds determined by the energetic criterion is smaller than that by the geometric one. This deficiency of the energetic criterion results in longer hydrogen bonding lifetime than that of the geometric criterion. Thus, an extended criterion involving both geometric and energetic conditions is recommended for hydrogen bonding analysis.