Рубрики:
DIFFUSION-LIMITED AGGREGATION
COLLOIDAL AGGREGATION
FRACTAL CLUSTERS
ANTICORRELATION
SIMULATIONS
DIFFUSION-LIMITED AGGREGATION
COLLOIDAL AGGREGATION
FRACTAL CLUSTERS
ANTICORRELATION
SIMULATIONS
Аннотация: Two- and four-point density correlation functions p(2)(r) and p(4)(r) are studied numerically and theoretically in computer-generated three-dimensional lattice cluster-cluster aggregates (CCA) with the number of particles N up to 20 000 in application to the light scattering problem. The ''pure'' aggregation algorithm is used, where subclusters of all possible sizes are allowed to collide. We find that large CCA clusters demonstrate pronounced multiscaling. In particular, the fractal dimension determined from the slope of p(2)(r) at small distances differs from that found from the dependence of the radius of gyration on the number of monomers (according to our data, 1.80 and 1.94, respectively). We also consider different functional forms for p(2) and their general properties and applicability. We find that the best fit to the numerical data is provided by the generalized exponential cutoff function with coefficients depending on N. The latter dependence is a manifestation of multiscaling. We propose some theoretical approaches for calculating p(4)(r), assuming p(2)(r) is known. In particular, we find the small-r asymptote for the p(4)(r) and verify it numerically. In addition, we find that p(4)(r) cannot be represented by a scaling dependence with a cutoff function, like p(2)(r) Instead, p(4)(r) is given by an expansion in terms of integer powers of r(2D-3), where D is the fractal dimension (approximate to 1.8 for CCA clusters).
WOS
Держатели документа:
UNIV WISCONSIN,DEPT CHEM,OFF CHANCELLOR,STEVENS POINT,WI 54481
UNIV WISCONSIN,DEPT PHYS & ASTRON,STEVENS POINT,WI 54481
RUSSIAN ACAD SCI,INST AUTOMAT & ELECTROMETRY,NOVOSIBIRSK 630090,RUSSIA
RUSSIAN ACAD SCI,SIBERIAN BRANCH,LV KIRENSKY PHYS INST,KRASNOYARSK 660036,RUSSIA
ИФ СО РАН
Доп.точки доступа:
Markel, V. A.; Shalaev, V. M.; Poliakov, E. Y.; George, T. F.