Angular dependence of the two-electron intex distribution

The probability density for the angle between the intracular (u) and extracular (R) coordinate vectors using both Hartree–Fock (HF) and explicitly correlated Kinoshita wave functions is presented. This angular density, A(θRu), and the angular-dependent intex density, X(R,u,θRu), are explored for the helium isoelectronic series from He to Ne8+ to study how electron pairs are distributed in atomic systems (both HF and exact). We demonstrate that the most probable angle depends significantly on the scalar values of R and u for both the HF and exact treatments. As R and u increase, the favoured angle for these densities approach 0 and π.