Basis-set-free density-functional quantum chemistry

Fully-numerical, non-basis-set molecular orbital calculations in coordinate space are reported for the first time on polyatomic systems. Self-consistent density-functional bond energy calculations have been performed on the ten-electron hydrides HF, H2O, NH3, and CH4, in addition to test calculations on the diatomics H2, N2, and F2, and the triatomic ion H+3. We find excellent precision for the present numerical algorithm, and very good agreement between the density-functional and experimental bond energies. Reliable basis-set-free quantum chemistry is now possible, at least in the density-functional theoretical framework.