An efficient numerical multicenter basis set for molecular orbital calculations: Application to FeCl4

The use of numerical solutions to atomlike single site potentials as a basis for molecular orbital calculations is investigated. The atomic Hamiltonian is modified by addition of a potential well to induce additional discrete levels with the desired spatial characteristics. The discrete variational method is employed, in the Hartree‐Fock‐Slater model, to compare levels obtained for FeCl4 using multiple‐scattering, conventional Slater‐orbital, and numerical basis sets. The numerical technique is shown to be an accurate and efficient method for treating general (non‐muffin‐tin) molecular potentials. The errors in energy levels due to the muffin‐tin approximation are calculated.