Extended Hückel calculation of repulsive interactions in noble gases

Repulsive potential energies for all of the possible pairs of atoms of the noble gases helium, neon, and argon are calculated by the semiempirical extended Hückel molecular orbital method. The agreement of the calculated energies with other theoretical results is significantly improved by computing overlaps using analytic approximations to the atomic Hartree–Fock atomic orbitals instead of the more commonly used Slater functions.