末端间矢量

末端间矢量是从聚合物的一个末端指向另一个末端的矢量，定义为

\vec{R} = \vec{R_{N}} - \vec{R_{O}} = \sum_{i = 1}^{N} \vec{r_{i}}

均方末端间矢量（均方末端距）定义为

\begin{matrix} ⟨ R^{2} ⟩ & = ⟨ \sum_{i} \vec{r_{i}} \cdot \sum_{j} \vec{r_{j}} ⟩ \\ = \sum_{i} \sum_{j} ⟨ \vec{r_{i}} \cdot \vec{r_{j}} ⟩ \\ = \sum_{i} ⟨ \vec{r_{i}} \cdot \vec{r_{i}} ⟩ + 2 \sum \sum_{i < j} ⟨ \vec{r_{i}} \cdot \vec{r_{j}} ⟩ \end{matrix}

参考文献