Exact solution (within a double-zeta basis set) of the schrodinger electronic equation for water

Using recently developed theoretical techniques, it has been possible to achieve an exact variational solution of Schrodinger's Equation within a modest basis set of one-electron functions. The full configuration interaction for this system included a total of 256,473 {sup 1}A{sub 1} spin-and space-adapted configurations. Comparison with many-body perturbation theory proves to be quite interesting.