Determination of Bond Dissociation Energies

Endothermic Reactions and the Determination of Bond Dissociation Energies for Organometallic Fragments. The reaction of atomic nickel ion with molecular hydrogen to yield NiH+is substantially endothermic. Reaction cross sections for this process, measured using the ion beam apparatus shown in Figure 1, are displayed in Figure 3 for reactions 1 and 2 with HD as the neutral. 

Szwarc, M. Determination of Bond-Dissociation Energies, Ckem. Revs., 50, 75 (1951). 

DETERMINATION OF BOND DISSOCIATION ENERGIES BY THERMAL EQUILIBRIUM METHODS... 

The application of the method to the determination of bond dissociation energies in polyatomic molecules has been carried out, at least at first, in a less rigorous manner. The results are justified mainly by their self-consistency and also by their often remarkably close agreement with results obtained by different methods. For example, D(CH -H) was determined in two separate ways by electron impact, and the agreement between them was taken to show that errors due to kinetic energy effects were unlikely to be present. 

Although this paper is primarily concerned with inorganic free radicals and reactions of inorganic free radicals, it also discusses some unstable nitrogen compounds, and metastable atoms and molecules. The production, detection, and identification of free radicals, and the determination of bond-dissociation energies for the radicals, are considered in some detail. Radicals produced by heterogeneous reactions, such as the catalytic reactions on heated filaments in the mass spectrometer ion source, are not considered. 

The data listed in Table 9 for I atom attack on alkanes have largely been derived from studies of Benson, Golden and co-workers who have also reviewed the data for these systems with particular reference to their application to thermochemistry and the determination of bond dissociation energies [98]. 

As to another important aspect of the study of endothermic dissociative charge transfer, i.e. its application to the determination of bond dissociation energies of Vcirious molecules, we do not have enough space to describe it, and the reader is referred to the original papers [176, 181] for detailed discussion on individual molecules. 

Measurements of the photofluorescence thresholds have been very useful in the determination of bond dissociation energies and the value for Z) (SC—S) estimated from the threshold for CS(a Il) luminescence was in very good agreement with an earlier estimate reported by Okabe (see Table 3.5.5) which was derived from the threshold for CS( - -X0 fluorescence, excited via the (spin-forbidden) dissociation... 

Determination of Bond Dissociation Energies from Kinetic Measurements Macroscopic Description... 

The enthalpies of formation have been obtained either from equilibrium data, as for difluoromethylene, or calculated from kinetic determinations of bond dissociation energies (generally the R -H bond) via eq. (6). 

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