Articles you may be interested inOne-and two-body densities of carbon isoelectronic series in their low-lying multiplet states from explicitly correlated wave functions Electron correlation and noninteracting v -representability in density functional theory: The Be isoelectronic series One-and two-body densities in momentum space have been calculated for the atomic beryllium isoelectronic series starting from explicitly correlated multideterminant wave functions. The effects of electronic correlations have been systematically studied by comparing the correlated results with the corresponding Hartree-Fock ones. Some expectation values such as ͗␦(p ជ )͘, ͗p n ͘, ͗␦(p ជ 12 )͘, ͗p 12 n ͘, ͗␦(P ជ )͘, and ͗P n ͘, where p ជ , p ជ 12 , and P ជ stand for the electron-nucleus, interelectronic, and two-electron center-of-mass momentum coordinates, respectively, and the angular correlation coefficient have been obtained. All the calculations have been carried out by using the Monte Carlo algorithm.