Clusters, ballistic

Clusters resulting from a ballistic cluster-cluster aggregation process, where... 

The growth of films via SCBD can be viewed as a random stacking of particles as for ballistic deposition [33,34]. The resulting material is characterized by a low density compared to that of the films assembled atom by atom and it shows different degrees of order depending on the scale of observation. The characteristic length scales are determined by cluster dimensions and by their fate after deposition. Carbon cluster beams are characterized by the presence of a finite mass distribution and by the presence of different isomers with different stabilities and relativities. Due to the low kinetic energy of clusters in the supersonic expansion stable clusters can survive to the deposition, while reactive isomers can coalesce to form a more disordered phase [35]. 

Two-dimensional arrangements might be monolayers of clusters on a suitable substrate or two or more coupled ID arrays. While layers are accessible via self-assembly, LB, or electrodeposition, coupled arrays could be obtained by filling clusters into the parallel channels of a crystalline nanoporous solid. 2D networks of clusters might be precursors for simple neural networks, utilizing the Coulombic interaction between ballistic electrons in a 2D electron gas. This concept has been discussed by Naruse and in general introduces new possibilities for the interconnection approach in various fields, e.g. parallel processing and quantum functional devices. 

Table 1. Comparison of the statistically averaged optical parameters A, with those calculated with both orientation and statistical averaging, A), (/j ). Calculations for ballistic clusters built from gold particles with diameters rf = 15 and 30 nm, polymer shell thickness and refractive index s = 2.5 nm and n = A, respectively. All data are averaged over 100 independent cluster configurations.

Meakin, P. and Jullien, R. (1988). The effects of restructuring on the geometry of clusters formed by diffusion-limited, ballistic and reaction-limited cluster-cluster aggregation. J. Chem. Phys., 89, 246-250. 

Ballistic aggregation (Figure 7.10c). This is similar to DLA but the incoming monomers that are trapped by the cluster do not follow a Brownian path but straight lines. The agglomerate that results is a bit more porous than in the case of RLA but it is not fractal the dimension of the cluster is d (3 in space and 2 on a flat screen). 

For a realistic modelling of primary carbon black aggregates by ballistic cluster-cluster aggregation with rff= 1.9 and /)= 1.3, they came out with the following mathematical expression ... 

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