The Hartree-Fock calculations from figure 
were also
repeated to ensure that the new interaction reduces the CFSE present
in these calculations. The results are illustrated in
Figure . The new interaction is clearly also
successful in HF calculations, reducing the CFSE by a factor of about 3.
Figure: The energy per atom of diamond-structure silicon as a
function of simulation cell size, from HF calculations using the
Ewald electron-electron interaction and the new interaction.