A COMPARISON OF FINITE BASIS-SET AND FINITE-DIFFERENCE METHODS FOR THE GROUND-STATE OF THE CS MOLECULE

A comparison is made of the accuracy with which the total electronic e nergy can be calculated by using either the finite ba-sis set approach (the algebraic approximation) or finite difference methods in calcula tions using the Hartree-Fock model for the ground (x 1SIGMA+) state of the carbon monosulphide molecule, The CS molecule is considered as a prototype for systems containing atoms from different rows of the peri odic table. The convergence of the calculations carried out within the algebraic approximation is monitored by employing systematically cons tructed basis sets of increasing size. The dependence of the finite di fference calculations on the numerical grid employed is studied.