论文标题
在线性单ols的X射线散射和计算机模拟的相关微结构上
On the X-ray scattering pre-peak of linear mono-ols and the related micro-structure from computer simulations
论文作者
论文摘要
从实验（甲醇到1-甘油醇）获得的线性烷醇OH（CH2）N-1CH3的X射线散射强度I（K）和计算机模拟（甲醇至1-烷醇）的不同力场模型的实验，尤其是为了解释k-vecory的特性和散射范围，以解释不同力场模型的甲醇模拟（甲醇至1-nonanol）。 0.3a^{ - 1} -1a^{ - 1}。实验I（K）显示了两个明显的特征：峰前位置KP随着n的增加而降低，更有趣的是，振幅AP在1-丁醇时（n = 4）处于最大值。所有力场模型都很好地复制了第一个功能，而第二个功能则显示出强大的模型依赖性。模拟揭示了从n> 2的各种羟基组簇的形状。 KP与\ emph {meta-objects}的大小直接相关，该大小与与烷基尾部包围的簇相对应。在取消与域排序相关的原子-ATOM s（k）贡献方面，n = 4时AP周转的解释更多。烷基尾部的灵活性倾向于减少交叉贡献，从而揭示了该参数在模型中的关键重要性。具有全原子表示的力场在复制较小的烷醇n <6的预峰特征方面不太成功，这可能是因为它们模糊了电荷排序过程，因为所有原子都均具有部分电荷。分析清楚地表明，无法获得对I（k）特征的免费模型解释
The X-ray scattering intensities I(k) of linear alkanols OH(CH2)n-1CH3, obtained from experiments (methanol to 1-undecanol) and computer simulations (methanol to 1-nonanol) of different force field models, are comparatively studied, particularly in order to explain the origin and the properties of the scattering pre-peak in the k-vector range 0.3A^{-1}-1A^{-1}. The experimental I(k) show two apparent features: the pre-peak position kP decreases with increasing n, and more intriguingly, the amplitude AP goes through a maximum at 1-butanol (n=4). The first feature is well reproduced by all force field models, while the second shows a strong model dependence. The simulations reveal various shapes of clusters of the hydroxyl head-group, from n>2. kP is directly related to the size of the \emph{meta-objects} corresponding to such clusters surrounded by their alkyl tails. The explanation of the Ap turnover at n=4 is more involved, in terms of cancellations of atom-atom S(k) contributions related to domain ordering. The flexibility of the alkyl tails tend to reduce the cross contributions, thus revealing the crucial importance of this parameter in the models. Force fields with all-atom representation are less successful in reproducing the pre-peak features for smaller alkanols n<6, possibly because they blur the charge ordering process since all atoms bear partial charges. The analysis clearly shows that it is not possible to obtain a model free explanation of the features of I(k)
