Cluster-size effect

Y. Nosenko, A. Kyrychenko, R. P. Thummel, J. Waluk, B. Brutschy, and J. Herbich, Fluorescence quenching in cyclic hydrogen bonded complexes of I // pyrrolo[3,2 hjquinoline with methanol Cluster size effect. Phys. Chem. Chem. Phys. 9, 3276 3285 (2007). 

Cluster size effects on bound excited states of SO2... 

Lastly, we would like to mention here results of the two kinds of large-scale computer simulations of diffusion-controlled bimolecular reactions [33, 48], In the former paper [48] reactions were simulated using random walks on a d-dimensional (1 to 4) hypercubic lattice with the imposed periodic boundary conditions. In the particular case of the A + B - 0 reaction, D = Dq and nA(0) = nB(0), the critical exponents 0.26 0.01 0.50 0.02 and 0.89 0.02 were obtained for d = 1 to 3 respectively. The theoretical value of a = 0.75 expected for d = 3 was not achieved due to cluster size effects. The result for d = 4, a = 1.02 0.02, confirms that this is a marginal dimension. However, in the case of the A + B — B reaction with DB = 0, the asymptotic longtime behaviour, equation (2.1.106), was not achieved at all - even at very long reaction times of 105 Monte Carlo steps, which were sufficient for all other kinds of bimolecular reactions simulated. It was concluded that in practice this theoretically derived asymptotics is hardly accessible. 

Periquet V, Moreau A, Carles S, Schermann J, Desfrancois CJ (2000). Cluster size effects upon anion solvation of N-heterocyclic molecules and nucleic acid bases. J Electron Spectrosc Relat Phenom 106 141-151. 

Jalbout A, Adamowicz L (2002). Cluster size effects upon stability of adenine-methanolanions. Theoretical study. J Mol Struct 605 93-10. 

Lee S, Pan CY, Wu TP, Anderson SL (2005) Cluster size effects on CO oxidation activity, adsorbate affinity, and temporal behavior of model Aun/TiO catalysts. J Chem Phys 123 124710... 

These results are subsequently used to elucidate the most favored adsorption sites, the most favored adsorption modes, and overall reaction energies for specific surface reaction steps. From this data, we can begin to construct overall catalytic cycles and examine their likelihood in carrying out proposed process chemistry. More detailed reaction coordinate searches are required to analyze the actual mechanism, where transition states and corresponding activation barriers are rigorously computed. While the transition states found herein appear to be quite reasonable, the predicted activation barriers are slightly high. This may be the result of cluster size effects rather than the DFT accuracy. 

An additional test that is necessary is the careful analysis of the cluster-size effect. It is well known that the results of cluster-model calculations strongly depend on the... 

The existence of an approximate estimate of the strength of the copper-water interaction determined the choice of this system for the study of the cluster-size effect. The set of calculations for the adsorption of the water molecule at the three sites, top, bridge and hollow, was performed for each Cu cluster (n = 1,2,4,5,9,12) shown in Fig. 1. The adsorption energy, the distance of the molecule from the surface, and, for the top site, the tilt angle between the molecular axis of H2O and the normal to the surface were measured for all the clusters. 

Fig. 1. A smooth representation of the cluster size effect the ionization potential of Kn clusters versus the size n. At lower values of n there are deviations of the experimental values from this monotonic decline and this is one piece of evidence, for ma c numbers as further discussed in Sec. 5.

As clusters are built up from atoms, size-dependent properties emerge " Jortner has described the cluster size effects as the general expression X(7 = X(oo) +where X is the property, A is a constant, and f lies between 0 and 1. " " Size-dependent properties include... 

Cluster Size Effects and Metal-Support Interaction... 

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