Electronic and geometrical structures of Co<sub>n</sub> (n=6, 8, 9, 10, 12, 14) particles have been studied using both the density
functional theory and Hartree-Fock calculations. Structural and electronic differences to the corresponding clusters are
presented. We have tried to recognize which structure (fcc or bcc) is more preferable for these particles. A four-fold and
higher coordination of the Co atoms was found to be the particularly preferable coordination environment in small Co<sub>n</sub>
species. The key element of the Co particle is alsosuggested.
Electronic and geometrical structures of Co<sub>n</sub> (n=4, 6, 8) particles have been studied using both the density functional
theory and the Hartree-Fock calculations. Structural differences to the corresponding clusters are presented. Four-fold
coordination of the Co atoms was found to be a particularly preferable coordination environment in small Co<sub>n</sub> species.
The key element of the Co particle is suggested.
In this paper we present the estimation of average droplet radius in the polymer dispersed liquid crystal (PDLC) film by using optical transparency measurements in electric fields and following calibration by means of the Rayleigh-Gans approximation.
Was synthesized two copper (II) complexes and one nickel complex of N-benzylidene-aniline derivatives and their ligands. We have performed polarized FTIR spectroscopy and X-ray diffraction measurements in wide temperature range (0-220°C) in order to establish correlation's among molecular, crystal and mesophase structures. We provided comparison of the FTIR and X-ray diffractometry results between well known metallo-organic copper (II) complexes, which crystallizes in the monoclinic space group C2/c, with similar nickel complex. Investigated ligands and their metallo-mesogens are displaying the same sequence of the liquid crystalline phases -- only with higher melting temperature for metallo-complexes.
Recently photonic crystals with a three-dimensional ordered structure with periodicity of the optical wavelength have attracted attention from both fundamental and practical points of view. The physics and applications of photonic crystals have been active topic of research now. The application of photonic crystals is to create tunable band gap materials especially in visible spectra region, where the gap could be controlled by an external parameter. We have studied transmission and linear dichroism spectra of synthetic opal, refractive index n = 1,342, infiltrated with nematic liquid crystal with averaged refractive index n = 1,596 or with water n = 1,30 and alcohol n = 1,28. We demonstrating that the position of the stop band in the visible spectra is shifted by changing of refractive index of the infiltrated material or by changing the filling factor or by variation of an incidence angle of light.
Our report is on the observation of thermoelectric phenomena in polymer dispersed nematic liquid crystal (PDLC). We have performed electro-optical measurements of the PDLC composite material based on both polyvinylbutiral and epoxy resin matrix. Despite different preparation al methods of the PDLC films, they show at the same time both the properties of polymer and liquid crystal. A stable memory effect was observed in the investigated PDLC films.
Electrooptical characteristics of the polymer dispersed liquid crystal (PDLC) structure were estimated using Rayleigh-Gans scattering theory. This simple method suits for an approximate estimation of the influence of geometrical parameters of the PDLC structures on electrooptical characteristics. The conclusion has been made, that 'threshold' voltage of the electrooptical response is caused by geometrical parameters of the PDLC structures mainly, but not by the properties of the LC.
We report the results of an experimental investigation of changes of the electrooptical switching times in polymer dispersed nematic liquid crystal film caused by shear deformation. We conclude that this change is caused by geometrical parameters of the nematic liquid crystal droplets. The experimental results are in a good agreement with calculated formula.
Three ligands with different number of carbon atoms in alkoxy chain, their Cu(II) and Ni(II) metallomesogens were synthesized. Absorption, linear dichroism spectroscopy measurements in visible region and x-ray diffractometry measurements at heating-cooling cycles were performed. An influence of organic groups and Cu(II), Ni(II) ions on thermodynamic properties have been discussed.
A ligand and three metallo-organic complexes containing Nd<SUP>3+</SUP>, Tb<SUP>3+</SUP> and Er<SUP>3+</SUP> ions were synthesized. Absorption linear dichroism spectroscopy and domain structures investigations plus x-ray diffractometry measurements at heating-cooling cycles were performed. An influence of a rare earth metals on LC thermodynamic properties have been discussed.