The ionization potential of NF3: a G3 computational study on the thermochemical properties of NFx and NFx+ (x=1-3)

The adiabatic ionization potential (IP) of NFx (x = 1-3) and the enthalpies of formation of NFx and NFx+ have been computed using the Gaussian-3 (G3) theory. The obtained values are generally found in very good agreement with the experimental ones. However, the G3 enthalpy of formation of NF3+ at 0 K, 261.7 +/- 0.9 kcal/mol, and the adiabatic IP of NF3, 12.63 +/- 0.04 eV, differ appreciably from the experimental values of 269.6 kcal/mol and 13.00 +/- 0.02 eV, respectively, based on photoionization mass spectrometry [J. Berkowitz, J.P. Greens, J. Foropoulos, Jr., O.M. Neskovic, J. Chem. Phys. 8 1 (1984) 6166] and 268.2 kcal/mol and 12.94 +/- 0.01 eV, respectively, base d on photoelectron photoion coincidence spectroscopy [R. Ruede, H. Troxler, Ch. Beglinger, M. Jungen, Chem, Phys. Lett. 203 (1993) 477]. This confirms the discrepancy recently noted by Ricca [A. Ricca, Chem. Phys. Lett. 294 ( 1998) 454] between the theoretical and the experimental adiabatic IP of NF3 . (C) 2000 Elsevier Science B.V. All rights reserved.