Hydrogen cluster ions

Wineland, D.J., Ion traps for large storage capacity, mProceedings of the Cooling, Condensation, and Storage of Hydrogen Cluster Ions Workshop, Bahns, J.T., Ed., Menlo Park, 1987, p. 181. 

Paul W, Liicke, B, Schlemmer S, Gerlich D. (1995) On the dynamics of the reaction of positive hydrogen cluster ions (Hjto H23) with para and normal hydrogen at 10K. Int. J. Mass Spectrom. Ion Proc. 150 373-387. 

Fig. 6.5. Hydrogen cluster ions as thermometer. The competition between cluster growth and fragmentation leads to a stationary equihbrium distribution, for typical densities after a few seconds. The plotted mass spectra (H in black and DH+ in yellow) have been measured at 10 K with normal and para-hydrogen at a number density of 10 cm . In both cases the maximum of the distribution is n = 19 however, in n-H2 more is formed while P-H2 favors deuteration.

Hydrogen-bonded clusters are an important class of molecular clusters, among which small water clusters have received a considerable amount of attention [148, 149]. Solvated cluster ions have also been produced and studied [150, 151]. These solvated clusters provide ideal model systems to obtain microscopic infonnation about solvation effect and its influence on chemical reactions. 

This section briefly considers the proton H+, the hydride ion H, the hydrogen molecule ion H2, the triatomic 2-electron species H3+ and the recently established cluster species +... 

In order to elucidate the causes of the increased stability of the hydrolyzed cluster ions compared with the unhydrolyzed ions, further studies were made of the behaviour of [Te2X8]3 (where X = Cl,Br, or I) in solutions of hydrogen halides [43,52,80,87]. The studies were performed mainly in relation to the most stable and most readily synthesized [Tc2C18]3- ion (Fig. la) kinetic methods with optical recording were employed. The identity of the reaction products was in most cases confirmed by their isolation in the solid phase. The studies showed that the stability of the [Tc2X8]3 ions (where X = Cl, Br, or I) in aqueous solutions is determined by the sum of competing processes acid hydrolysis complex formation with subsequent disproportionation and dissociation of the M-M bonds, and oxidative addition of atmospheric oxygen to the Tc-Tc multiple bond. 

On the other hand, the alternative ADI mechanism views the processes as occurring where the excited neutral species are also first created through excitation processes. Thereafter, a subsequent intracluster neutral-neutral reaction leads to formation of hydrogenated clusters, (NH3)nH. Following excitation (reaction 7), ionization of the radical species then results in the observed protonated clusters ions as depicted as follows ... 

The potential of naked cluster ions (416), for example Bi53+, for catalysis has been noted (35), but hydrogenations have not yet been reported. 

S. Re and Y. Osamura, Size-dependent hydrogen bonds of cluster ions between phenol cation radicals and water molecules a molecular orbital study, J. Phys. Chem. A, 102 (1998) 3798-3812. 

In the mass spectrometric investigations of most hydrogen-bonded clusters, the protonated clusters form the dominant cluster ions as a result of a rapid proton transfer reaction (Mark and Castleman 1985). Castleman and coworkers have extensively investigated the neat expansions of methanol (Morgan and Castleman 1987, 1989 Morgan et al. 1989 Zhang et al. 1991) and observed the protonated cluster ions to form the most intense cluster series. In the case of methanol, the exoergic proton transfer reaction may be written as ... 

Figure 9-1 Possible structures for the hydroiiium ion. (a) The species H9O4 has been observed in the solid state and may be an important contributor in aqueous solution, (b) The species (H20)2iH exhibits a dodecahedral caged stracture in mixed water-trimethylamine cluster ions. The hydroniiim ion (not shown) is encased in the hydrogen-bonded cage with 10 non-hydrogen-bonded protons protaiding from its surface. S. Wei, Z. Shi, and A. W. Castleman, Jr., J. Chem. Phys, 1991, 94, 3268. Structure reproduced by courtesy of the American Institute of Physics.

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