A comparison of finite basis set and finite difference Hartree-Fock calculations for the open-shell (X2Σ+) molecules BaF and YbF

A comparison is made of the accuracy with which the total electronic energy can be calculated by using the finite basis set approach (the algebraic approximation) and the finite difference method in calculations employing the Hartree-Fock model for the open shell ground. (X(2)Sigma(+)) states of the fluorides BaF and YbF. The convergence of the calculations carried out within the algebraic approximation is monitored by employing systematically constructed basis sets of increasing size. The difference between the finite basis set and finite difference Hartree-Fock energies is 2.6 muE(h) for BaF and 2.8 muE(h) for YbF. Dipole moments determined within the algebraic approximation are also compared with the corresponding finite difference expectation values.