For a first test, the optimisation procedure was set up using 10,000 configurations generated by a VMC calculation, using the best parameters so far obtained for ¸. The function was hard wired to use those parameters. It was intended that if the inclusion of produced a large change in the wavefunction and therefore the charge density, would also have to be included in the optimisation to allow it to adjust to these changes.
Only the 
and 
orders of the Chebyshev expansion were used
in (
).
This gave a total of 12 parameters to be optimised [6 for the
parallel and 6 the for anti-parallel functions].
Four separate optimisations were performed for values of the range of
, L=3.0,3.5,4.0,5.0. These corresponded to an average number of
electron pairs around each ion contributing to of 3,5.5,7,12
respectively.
The size of naturally increased with L as more electron pairs
were included, but the optimised parameters were still very small.
The best result was achieved by choosing L=4.0 (larger values proved
to be unstable in the optimisation routine.)
This produced a lowering of the energy beyond
the optimised energy of about 0.01eV per atom. As with the
optimisation of ¸, the variance again showed little change; in the
best result it dropped by 0.01 units.