Electron correlations in atomic shells: Systematics of high-angular-momentum admixtures

The systematic admixture of high angular momentum into the low-lying states of atoms constitutes a class of correlated electron motion resulting from a single physicomathematical mechanism. In the region of configuration space where the mean-square distance of electrons from the nucleus ($R^2=\Sigma {i=1\mathrm{}}^N\frac{r_i^2}{N}$) is less than its expectation value, the atomic shell structure is strongly perturbed. In the limit $R\to 0$ high angular momentum becomes more favorable energetically and the shell structure approaches that of a Fermi gas. Results include a list of configurations which mix strongly with ground states of atoms from beryllium to argon.