In water clusters

Lavrich D J, Buntine M A, Serxner D and Johnson M A 1993 Excess energy-dependent photodissociation probabilities for Ot in water clusters O, I 1i Chem. Rhys. 99 5910-16... 

Lee et al.97 investigated the HF, HC1, and H2S dissociation reactions in water clusters. A good agreement between the DFT(BLYP) and the MP2 results was reported for binding energies (within 2 kcal/mol) and geometries. The studies showed also that at least four water molecules are needed for ionic products of dissociation to coexist. 

Thirumalai, D. Wallqvist, A. Berne, B.J., Path-integral Monte Carlo simulations of electron localization in water clusters, J. Stat. Phys. 1986, 43, 973-984... 

Liquid water is an essential component of most terrestrial chemical processes, including those of living organisms. The cooperativity of H-bonding in water clusters is therefore of primary importance for understanding the structure and dynamics of pure water, as well as a vast spectrum of aqueous solvation phenomena in biotic and abiotic systems. In the present section we examine cooperativity effects for a... 

Trajectory calculations for proton transfer and ionization in water cluster,112 116 isomerization,117 and various types of unimolecular reactions6,118 128 have been carried out, and the analyses on time course of the reaction, product ratio, and product energy distribution were reported. 

Quantum Mechanical Studies of the Hydrogen Bond in Water Cluster Systems. 

In a very ingenious experiment the authors of Ref. (401) could get a direct probe of the HC1 dissociation in water clusters pump-and-probe femtosecond spectroscopy. They observed that the dissociation process takes place spontaneously in the presence of five water molecules, while the dissociation of HC1 in smaller clusters can only be photoinduced. Theoretical predictions reported in Ref. (386) fully confirm these experimental findings. In fact... 

Milet A, Moszynski R, Wormer PES, Van der Avoird A (1999) Hydrogen bonding in water clusters pair and many-body interactions from symmetry-adapted perturbation theory. J Phys Chem A 103 6811-6819... 

Milet A, Struniewicz C, Moszynski R, Wormer PES (2001) Theoretical study of the protolytic dissociation of HG in water clusters. J Chem Phys 115 349-356... 

Water clusters containing simple ions are another area of current experimental and theoretical interest. Accordingly, they are also the subject of EA studies. Chaudhury et al. [113] have used EA methods on empirical potentials to obtain optimized structures of halide ions in water clusters, which they then subjected to AMI calculations for simulation of spectra. EA applications to alkali cations in TIP4P water clusters [114,115] have led to explanations of experimental mass-spectroscopic signatures of these systems, in particular the lack of magic numbers for the sodium case and some of the typical magic numbers of the potassium and cesium cases, and the role of dodecahedral clathrate structures in these species. 

Lubin, M.I., Bylaska, E.J., and Weare, J.H., Ab initio molecular dynamics simulations of aluminum ion solvation in water clusters, Chem. Phys. Lett., 322, 447, 2000. 

We have also studied the behavior of gas-phase radicals, such as the hy-droperoxyl radical (HO2) [62], in water clusters which is important in atmospheric science (Figure 16.4). The hydroperoxyl radical is a major species in the HOx chemical family [2] that affects the budgeting of many chemical systems in the atmosphere. The HOx system plays a central role (along with the OH radical) in oxidative chemistry in the troposphere and ultimately controls the production rate of tropospheric ozone [7,16]. It is hence considered significant in atmospheric [2,5] and combustion chemistry [184]. Recent theoretical studies [16,17] have indicated the HO2 radical to possess stable interactions with water clusters. Such stability provides an important sink for HOx compounds [16,17,61,185] in the troposphere. As a result, the structural and dynamical features of water clusters play a vital role on HO2 related chemistry. 

Solvation effects at the transition-state level of electron-transfer reactions is a field that is opening up by means of clusters reactions. Reactions within clusters (see Section 2.7) or at the surface of clusters (see Section 2.8) provide an experimental tool to observe the effect of gradual solvation on electron-transfer reactions. Femtosecond methods appear highly valuable for characterizing the electron transfer in reactions within clusters, since in neutral clusters the electrostatic effects of solvation will show up intensely at the electron-transfer level and for a short period of time, before the products are fully developed. In the gas phase the solvation of electrons is directly sensed by photoelectron spectroscopy, as exemplified in the (nonreactive) case of ultrafast solvation of electrons in water clusters [305]. 

D. Chesnut and B. Rusiloski, A study of NMR chemical shielding in water clusters derived from molecular dynamics simulations, J. Molec. Struct. (THEOCHEM), 314 (1994), 19-30. 

J.E. Combariza, N.R. Kestner and J. Jortner, Energy-structure relationships for microscopic solvation of anions in water clusters, J. 

Tu, Y. and Laaksonen, A. (2005) Quantum Chemistry Study of Monomer Electronic Properties in Water Clusters and Liquid Water and Methanol. Int. J. Quantum Chem., 102, 888-896. 

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