Chris L. Haynes

Collision-induced dissociation of N3+ (X3Σ−) with Ne, Ar, Kr, and Xe

Abstract A guided-ion beam mass spectrometer is used to examine the collision-induced dissociation of ground state N 3 + ( 3 Σ − ) from thermal to 20 eV energy with Ne, Ar, Kr, and Xe. The product distribution observed in these systems varies substantially, a result that can be attributed to the large variation in the polarizabilities and ionization energies of the rare gases. The threshold for appearance of N + in these systems is measured to be 3.74 ± 0.08 eV and is equated with the N + N 2 bond energy. The adiabatic charge transfer reaction of N 3 + with Xe allows a determination of the ionization energy of N 3 as 11.10 ± 0.04 eV, in good agreement with a literature value determined by photoelectron spectroscopy. This information allows the heats of formation of N 3 and N 3 + to be determined as 4.61 ± 0.09 and 15.67 ± 0.08 eV, respectively. This thermodynamic information is compared with other available values. We also measured the adiabatic bond energies D 0 (N + Ar) = 1.22 ± 0.46 eV, D 0 (Kr + N) = 1.38 ± 0.13 eV and D 0 (Xe + N) = 0.65 ± 0.10 eV.

Guided ion-beam determination of the Co+-H2 bond dissociation energy

Abstract A guided ion-beam tandem mass spectrometer with a flow tube ion source is used to determine the 0 K bond dissociation energy of Co + -H 2 from ligand exchange of CoCH 4 + with D 2 and from collision-induced dissociation (CID) of CoH 2 + + Xe. Given D 0 (Co + -CH 4 ) = 0.93 ± 0.06 eV determined in our labs, the endothermicity of the ligand exchange reaction provides D 0 (Co + -D 2 ) = 0.74 ± 0.07 eV. The direct CID kof CoH 2 + process yields D 0 (Co + -H 2 ) = 0.82 ± 0.11 eV. After zero-point energy corrections, the average of these two results yields 0.76 ± 0.10 eV. This values agrees nicely with those determined by equilibrium methods and theory.