Abstract
A comparison is made of the accuracy with which the total electronic energy can be calculated by using either the finite basis set approach (the algebraic approximation) or finite difference methods in calculations employing the Hartree—Fock model for the open shell ground (X2Σ+) states of the 13-electron systems BeF, BO, CN and N+ 2. The convergence of the calculations carried out within the algebraic approximation is monitored by employing systematically constructed basis sets of increasing size. The accuracy of the finite difference calculations is assessed by employing two grids of different sizes, one of 32 617 points and the other of 132 385 points. The total Hartree—Fock energies supported by these two grids differ by less than 0.05 μE h. The average difference between the finite basis set and finite difference Hartree—Fock energies is 1.3 μE h. Dipole moments determined within the algebraic approximation are compared with the corresponding finite difference expectation values for the neutral species.