Consider the Kohn-Sham equation \begin{align} \left( - \frac{\hbar^2}{2m} \nabla^2 + \nu_\mathrm{eff}(\mathbf{r}) \right) \varphi_j(\mathbf{r}) &= \varepsilon_j\varphi_j(\mathbf{r}) \end{align} The external potential will be considered the interaction potential of electrons and nuclei.
Then \begin{align} \nu_{eff}=-\sum_{j}^{K} \frac{e^2 \, Z_{j}}{|\mathbf{r_1}-\mathbf{R_j}|}+\int\frac{n(\mathbf{r_2})e^2}{r_{12}}\mathbf{dr_2} +\nu_{xc} \end{align}
This equation is solved by the method of a self-consistent field: $\varphi$ are first set, then $n$ is calculated from them, then the effective functional $\nu_{eff}$ is calculated.
However, I do not understand something.
At each step of calculating the effective potential, the term denoting the interaction of nuclei with electrons is constant? $r_{12}$ is the distance between electrons. In terms of this model, no changes in the coordinates of electrons occur at each step?