The dissociation energies of the positive ions NH+3, NF+3, PH+3, PF+3 and PCl+3

The gas-phase thermochemistry of PCl4+: A test of lattice energy calculations

“…The 298 K enthalpies of formation of PCl 3 and Cl are −288.7 ± 5.4 and 121.3 kJ mol −1 , respectively [31]; these sum to −167.4 kJ mol −1 . The ionization energy of PCl 3 is 9.90 eV (955.2 kJ mol −1 ) at 0 K [8], which can be adjusted up by 1.26 kJ mol −1 to give the ionization energy at 298 K. This value uses the ion convention [3], where the heat capacity of the electron is taken to be zero. The IE can be added to the enthalpy of formation of [PCl 3 + Cl] to give f H 298 = 789 kJ mol −1 for [PCl 3 + + Cl + e − ].…”

“…In this case, the availability of a precisely measured ionization energy, IE(PCl 3 ) = 9.90 ± 0.01 eV [8], is particularly important (1 eV = 96.485 kJ mol −1 ). The history of measurements of this value is detailed on the NIST database [3].…”

Experimental and ab initio study of the infrared spectra of ionic species derived from PF5, PF3, and F3PO and trapped in solid neon

“…The first photoelectron band of PF 3 also has a gradual onset, with an estimated value 9 of 11.57 eV for the adiabatic ionization potential of that molecule. Subsequent photoionization 10 and photoion-photoelectron coincidence 11 ͑PIPECO͒ studies refined the position of the first ionization potential of PF 3 to 11.38 eV. Observations by Tuckett and co-workers 12 of the fluorescence excitation spectra of np Rydberg states of PF 3 between 9 eV and 13 eV indicate that PF 3 ϩ , like PF 3 , should possess a pyramidal structure, but that the deviation from planarity of the cation should be less than that of the uncharged molecule.…”

The infrared spectra of the NH3-dn+ cations trapped in solid neon

“…Samson and co-workers 41 measured NH 2 ϩ :NH 3 ϩ branching ratios of 1.08 and 1.21 at 16.67 and 16.85 eV ͑the positions of the two neon resonance emissions͒, respectively. A somewhat more recent threshold photoelectronphotoionization study 12 found that at 16.5 eV only 5% of the ion product was NH 3 ϩ . In contrast, a very recent study 42 of the ionization of NH 3 by collision with metastable neon atoms gave NH 2 ϩ :NH 3 ϩ ratios between 0.65 and 0.75.…”

“…This low-energy signal was attributed to a ''hot band'' arising from 2 Љϭ1. Several later studies [10][11][12][13] instead attributed the 10.07 eV peak to the ionization of ground-state NH 3 . However, other recent studies [14][15][16][17] have provided definitive support for the earlier attribution of this peak to the ''hot band.'…”