Approximate full configuration interaction calculations of total energies, harmonic vibrational frequencies and equilibrium bond distances on F2, BF, C2, CN+ and NO+ molecules in a DZ + P basis set

The results of ab initio full configuration interaction (FCI) calculations of the total energies, harmonic vibrational frequencies and equilibrium bond distances on F2, BF, C2, CN+ and NO+ in a double-zeta basis set augmented with polarization functions (DZ + P) are presented and discussed. The full CI calculations have been carried out by combining selected configuration interaction (CI) and second-order perturbation theory (PT). Fast convergence of CI + PT approach with reduced configuration selection threshold is demonstrated. Great attention is paid to the comparison of the FCI results presented with other methods.