"However, accurate quantum-mechanical calculations (starting in the 1970s)... singly occupied orbitals are less effectively screened or shielded from the nucleus, so that such orbitals contract and electron–nucleus attraction energy becomes greater in magnitude (or decreases algebraically)."
https://en.wikipedia.org/wiki/Hund%27s_rules:
Where do I find these calculations, papers, or data?
Is the source explaining the quote the "Hartree-Fock self consistent field calculations for the wavefunctions of atoms?" or Cowan's Code?