Distribution of $r_{12}\cdot p_{12}$ in quantum systems

Yves A. Bernard, Pierre-Francçois Loos, Peter M. W. Gill

We introduce the two-particle probability density $X(x)$ of $x={\mathbf{r}}_{12}\cdot {\mathbf{p}}_{12}=\left({\mathbf{r}}_1-{\mathbf{r}}_2\right)\cdot \left({\mathbf{p}}_1-{\mathbf{p}}_2\right)$. We show how to deri…