Collision-induced dissociation energy transfer

Schultz R H and Armentrout P B 1991 Reactions of NJwith rare gases from thermal to 10 eV center of mass energy collision induced dissociation, charge transfer, and ligand exchange Int. J. Mass Spectrom. Ion Proc. 107 29-48... 

Collision-induced dissociation a transfer of energy from monoatomic species such as He, Xe, etc., in inelastic collisions results in a population of the excited states of the polyatomics, which, in turn, may result in their subsequent dissociation. Here, purely mechanistic considerations are helpful to select appropriate gases for selected polyatomic species. 

Fig. 10. Absolute cross sections in A2 plotted against the H2 vibration level v for charge transfer (CT) and collision-induced dissociation (CID) for collisions of H (v) + H2. [15] The laboratory collision energies are given on each panel the center of mass energies are half as great. The cross sections were normalized to the absolute values reported by Lee et al. [36] at 16 eV lab those cross sections for v = 0-6 are also shown in panel (c)...

Another kind of indirect evidence for complex formation is found in the study of collision-induced dissociation of D3 by Leventhal and Friedman [135]. They found in tandem mass spectrometer experiments that the energy threshold (CM) of the reaction D3 -hX- D + D2 + Xis independent of X, where X = He, He, and Ne. This means the whole of the energy available to drive the reaction (= CM energy) is always used. Some sort of XD3 complex would be necessary for this complete energy transfer. 

Efficient conversion of translational kinetic energy into internal energy has also been discovered for endothermic processes other than atom transfer, such as charge transfer [176—179], dissociative charge transfer [94,176, 180,181] and collision-induced dissociation [98, 169]. 

Investigations of collision processes with molecules in these selectively populated levels f) yields the dependence of collision cross sections on the vibrational energy for collision-induced dissociation as well as for energy transfer into other bound levels of the molecule. Since the knowledge of this dependence is essential for a detailed understanding of the collision dynamics, a large number of theoretical and experimental papers on this subject have been published. For more information the reader is referred to some review articles and the literature given therein [1039, 1045, 1051-1053]. 

A variety of thermochemical data were obtained for negatively charged metal complexes. For example, appearance energy measurements photodissociation, energy-resolved, collision-induced dissociation, electron-, proton- and anion-transfer reactions to and from negatively charged ions, were all used for obtaining a variety of thermochemical parameters for ions, molecules, and radicals. 

This book deals with reactions only. However, other processes investigated by beam methods are relevant to reactive scattering. Non-reactive scattering in reactive systems provides valuable complementary information. So do studies at energies beyond those where new chemical bonds are formed. The reader is further referred to related experiments on inelastic scattering, charge transfer, dissociative charge transfer, and collision-induced dissociation. ... 

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