Effect of cluster size

N20 decomposition over (p-oxo)(p-hydroxo)di-iron complex supported by ZSM-5 zeolite effect of cluster size on DFT energy profile... 

Structural effects have also been observed in Ar HCl clusters with n = 1 and 2 (Garcia-Vela et al. 1994). In this case, the effect of cluster size on the cage effect depends on the excitation energy of HI and on the specific region of the potential surface that it accesses. 

Effect of Cluster Size on Chemical and Electronic Properties... 

Effects of cluster size and geometrical structure on valence... 

Weber, W.A. and Gates, B.C. (1998) Rhodium supported on faujasites effects of cluster size and CO ligands on catalytic activity for toluene hydrogenation. 

Fig. 2, The effect of cluster-size on the prediction of binding energies. A comparison of DFT-predicted (data...

Fig. 6 The effects of cluster size on adsorbate-induced surface (cluster) relaxation. A) Oxygen chemisorption on Pd6, and B) oxygen on PdiQ.

Careful analysis of both powder X-ray dilfraction and EXAFS spectroscopic data located the cadmium sulfide as (CdS)4 cubes occupying the space within sodalite cages, with the Cd ions coordinated to framework oxygen atoms (Fig. 6.10). Furthermore, the clusters were observed to order between adjacent sodalite cages, to give superclusters or a superlattice structure. In subsequent work, a variety of compounds and elements have been prepared as well-defined clusters within zeolite frameworks, including metal oxides, selenides and phosphides, and these have been studied mainly with the view of determining the effects of cluster size on optical and electronic properties. 

We next consider the effect of cluster size on the adiabatic IP and EA of a naked metallic cluster. From Equation (10a), IP and EA for a spherical metallic cluster (u nm) are related to those for the planar bulk metal a oo) in the same medium by... 

In the present work, information about the potential energy surfaces for these systems is obtained by the BAC-MP4 method [28-33]. This method has been very successful for predicting the thermochemistry of molecules and radical species, and has been extended to calculating the potential information along reaction paths needed for the variational transition state theory calculations. In the latter case, the method has been shown to be capable of quantitative predictions for a gas phase chemical reaction [33]. In the present study our interests are in estimates of the order of magnitude of reaction rates, and in studies of qualitative trends such as the effect of cluster size on the magnitude of quantum tunneling. The methods employed here are more than adequate for these types of studies. 

The effects of cluster size and dendrimer generation were also investigated. Measuring the catalytic activities of a series of Cu PAMAM—OH(Gg), n = 10, 20, 30, 40, 50, 60, in model reaction, hydrogenation of 2-hexanone, an inverse relationship between conversion and the molar ratio [Cu ]/ [PAMAM—OH(Gg)] was established (Fig. 6.26a). 

Although the energy decompositions discussed so far provide a rather detailed understanding of the interaction of adsorbates with clusters, it remains an open question how accurately the cluster calculations mimick chemisorption. Among the many studies of the effect of cluster size, there are two on the Cu /CO system which used energy decomposition to consider the variation of the various energy contributions with cluster size and shape (Post and Baerends [26], and Hermann, Bagus, Nelin [84]. 

The effect of cluster size on reaction barriers of the proton exchange reactions discussed in this work is displayed in Fig. 5 where activation energies computed using PBE/DNP are plotted against the cluster size, that is, 5T, 20T, 28T, 38T, 96T, and P models. For all alkanes, proton exchange barriers are reduced by around 5 and 10 kcal/mol when expanding from 5T to 38T and from 38T to 96T,... 

For the study of the effect of cluster size, all parameters were kept constant save for the size of the deposited clusters. As a representative coverage 0.04 e/nm was chosen, since for Ptn at this coverage the hydrogen evolution has not yet reached saturation, as described in the previous section. As reported above for different coverages, all the different sized samples show a linear increase of the amount of H2 over time (Fig. 5.29a), which again proves samples are stable over the course of the experiment. Figure5.29b shows the hydrogen evolution per hour (//2/h) for... 

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