Pulsed field-ionization photoelectron-photoion coincidence study of the process N2+hν→N++N+e-:: Bond dissociation energies of N2 and N2+ -: art. no. 074330

We have examined the dissociative photoionization reaction N-2+h nu -> N++N+e(-) near its threshold using the pulsed field-ionization photoelectron-photoion coincidence (PFI-PEPICO) time-of-flight (TOF) method. By examining the kinetic-energy release based on the simulation of the N+ PFI-PEPICO TOF peak profile as a function of vacuum ultraviolet photon energy and by analyzing the breakdown curves of N+ and N-2(+), we have determined the 0-K threshold or appearance energy (AE) of this reaction to be 24.2884 +/- 0.0010 eV. Using this 0-K AE, together with known ionization energies of N and N-2, results in more precise values for the 0-K bond dissociation energies of N-N (9.7543 +/- 0.0010 eV) and N-N+ (8.7076 +/- 0.0010 eV) and the 0-K heats of formation for N (112.469 +/- 0.012 kcal/mol) and N+ (447.634 +/- 0.012 kcal/mol).