\documentclass[12pt]{article} \begin{document} \begin{eqnarray*} E_{LJ} & = & 4 \epsilon \left[ \left(\frac{\sigma}{r}\right)^{12} - \left(\frac{\sigma}{r}\right)^6 \right] \\ E_{qq} & = & \frac{q_i q_j}{r} \\ E_{qp} & = & \frac{q}{r^3} (p \bullet \vec{r}) \\ E_{pp} & = & \frac{1}{r^3} (\vec{p_i} \bullet \vec{p_j}) - \frac{3}{r^5} (\vec{p_i} \bullet \vec{r}) (\vec{p_j} \bullet \vec{r}) \end{eqnarray*} \begin{eqnarray*} F_{qq} & = & \frac{q_i q_j}{r^3} \vec{r} \\ F_{qp} & = & -\frac{q}{r^3} \vec{p} + \frac{3q}{r^5} (\vec{p} \bullet \vec{r}) \vec{r} \\ F_{pp} & = & \frac{3}{r^5} (\vec{p_i} \bullet \vec{p_j}) \vec{r} - \frac{15}{r^7} (\vec{p_i} \bullet \vec{r}) (\vec{p_j} \bullet \vec{r}) \vec{r} + \frac{3}{r^5} \left[ (\vec{p_j} \bullet \vec{r}) \vec{p_i} + (\vec{p_i} \bullet \vec{r}) \vec{p_j} \right] \end{eqnarray*} \begin{eqnarray*} T_{pq} = T_{ij} & = & \frac{q_j}{r^3} (\vec{p_i} \times \vec{r}) \\ T_{qp} = T_{ji} & = & - \frac{q_i}{r^3} (\vec{p_j} \times \vec{r}) \\ T_{pp} = T_{ij} & = & -\frac{1}{r^3} (\vec{p_i} \times \vec{p_j}) + \frac{3}{r^5} (\vec{p_j} \bullet \vec{r}) (\vec{p_i} \times \vec{r}) \\ T_{pp} = T_{ji} & = & -\frac{1}{r^3} (\vec{p_j} \times \vec{p_i}) + \frac{3}{r^5} (\vec{p_i} \bullet \vec{r}) (\vec{p_j} \times \vec{r}) \\ \end{eqnarray*} \end{document}