Dresden 2006 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 2: Colloids and Nanoparticles

CPP 2.8: Vortrag

Montag, 27. März 2006, 12:00–12:15, ZEU 160

Lattice dynamics of two-dimensional colloidal crystals — •Pavel Dyshlovenko — Ulyanovsk State Technical University, 32 Severny Venets Street, Ulyanovsk 432027, Russia

Electrostatic interaction in two-dimensional colloidal crystals obeying the non-linear Poisson-Boltzmann equation is studied numerically. The force constants, which are the coefficients of the energy quadratic form of the crystal, are obtained for hexagonal and quadratic crystal lattices. The normal modes of oscillations and low frequency elastic properties of colloidal crystals are then calculated for a broad range of lattice constants and particles’ parameters. Particular attention is given to many-particle effects in the crystals.

Significant discrepancy between the results of computer experiments and predictions of the harmonic crystal theory based on the idea of pair interaction was detected. The unified approach to quantitative estimation of many-particle effects and validity of the approximation of the nearest-neighbour interaction is proposed. It is shown that the contribution of many-particle interaction into the total electrostatic interaction in colloidal crystals is surprisingly significant for a broad range of crystal lattice constants and particles’ sizes and charges.