+ & = & \frac{-\hbar^2}{2m} \sum_{i=1}^N \int d\vec{r} d\vec{r}' \,
+ \langle \Psi | \vec{r} \rangle \nabla_{\vec{r}_i}
+ \langle \vec{r} | \vec{r}' \rangle
+ \nabla_{\vec{r}'_i} \langle \vec{r}' | \Psi \rangle\\
+ & = & \frac{-\hbar^2}{2m} \sum_{i=1}^N \int d\vec{r} d\vec{r}' \,
+ \nabla_{\vec{r}_i} \langle \Psi | \vec{r} \rangle
+ \delta_{\vec{r}\vec{r}'}
+ \nabla_{\vec{r}'_i} \langle \vec{r}' | \Psi \rangle\\