MRD-CI POTENTIAL SURFACES USING BALANCED BASIS-SETS .6. CORRELATION OF BOND ORDER WITH BOND FUNCTION COMPOSITION FOR 1ST-ROW DIATOMIC-MOLECULES

This article presents theoretical calculations on bond energies for the first-row diatomics C2, CN, CO, CF, N2, NO, NF, O2, FO, and F2, which vary in bond order from one to three. The atomic-centered basis functions are systematically augmented with bond functions (BFs), which range in composition from (sp) to 2(spd), to determine the basis set which yields a dissociation energy closest to the experimental D(e). A strong correlation is found to exist between the bond order and the number of BFs required in the optimum basis set. Based on these results, we are able to predict the optimum composition of the BF basis which should be added to a DZP-quality AO basis set for a case in which only the bond order is known. These optimized BF basis sets are shown in the accompanying article to give more accurate potential curves than larger basis sets without bond functions.