APPROXIMATE FULL CONFIGURATION-INTERACTION CALCULATIONS OF TOTAL ENERGIES, HARMONIC VIBRATIONAL FREQUENCIES AND EQUILIBRIUM BOND DISTANCES ON F2, BF, C-2, CN-SET( AND NO+ MOLECULES IN A DZ+P BASIS)

The results of ab initio full configuration interaction (FCI) calculat ions of the total energies, harmonic vibrational frequencies and equil ibrium bond distances on F-2, BF, C-2, CN+ and NO+ in a double-zeta ba sis set augmented with polarization functions (DZ + P) are presented a nd discussed. The full CI calculations have been carried out by combin ing selected configuration interaction (CI) and second-order perturbat ion theory (PT). Fast convergence of CI + PT approach with reduced con figuration selection threshold is demonstrated. Great attentions paid to the comparison of the FCI results presented with other methods.