Journal of Chemical Physics, Vol.104, No.15, 5883-5891, 1996
Ab-Initio Investigation of the N-2-HF Complex - Accurate Structure and Energetics
Augmented correlation consistent basis sets of double (aug-cc-pVDZ), triple (aug-cc-pVTZ), and modified quadruple zeta (aug-cc-pVQZ’) quality have been employed to describe the N-2-HF potential energy surface at the Hartree-Fock level and with single reference correlated wave functions including Moller-Plesset perturbation theory (MP2, MP3, MP4) and coupled cluster methods [CCSD, CCSD(T)]. The most accurate computed equilibrium binding energies D-e are cm(-1) (with counterpoise correction) 810 cm(-1) (MP4/aug-cc-pVQZ’) and 788 cm(-1) [CCSD(T)/aug-cc-pVQZ’]. Estimated complete basis set limits of 814 cm(-1) (MP4) and 793 cm(-1) [CCSD(T)] indicate that the large basis set results are essentially converged. Harmonic frequencies and zero-point energies were determined through the aug-cc-pVTZ level. Combining the zero point energies computed at the aug-cc-pVTZ level with the equilibrium binding energies computed at the aug-cc-pVQZ’ level, we predict D-0 values of 322 and 296 cm(-1), respectively, at the MP4 and CCSD(T) levels of theory. Using experimental anharmonic frequencies, on the other hand, the CCSD(T) value of D-0 is increased to 415 cm(-1), in good agreement with the experimental value recently reported by Miller and co-workers, 398+/-2 cm(-1).
Keywords:CONFIGURATION-INTERACTION CALCULATIONS;CORRELATED MOLECULAR CALCULATIONS;VIBRATIONAL ROTATIONAL ANALYSIS;HYDROGEN-FLUORIDE DIMER;WEAKLY-BOUND COMPLEXES;GAUSSIAN-BASIS SETS;WAVE-FUNCTIONS;BENCHMARK CALCULATIONS;INFRARED-SPECTROSCOPY;INTERMOLECULAR FORCES