Наукові видання. Фізичний факультет

Постійне посилання колекціїhttps://ekhnuir.karazin.ua/handle/123456789/114

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Absorption spectra of layered ZnI2 and K2ZnI4 compounds intercalated by СО2
(Institute for Single Crystals, 2009) Yunakova, O.N.; Miloslavsky, V.K.; Kovalenko, E.N.; Makovetsky, E.D.
The absorption spectra of thin films of ZnI2 and K2ZnI4 layered compounds intercalated with СО2 molecules have been investigated in temperature interval from 90 to 240 K. It is found that the intercalation results in high-frequency shift of exciton bands and their broadening. Considering the structure of ZnI2 and K2ZnI4 crystal lattices, the most probable positions of СО2 molecules in spacings between layers of compounds have been established. It is shown that, in K2ZnI4 compound, unlike ZnI2, there are two position types of intercalant molecules with molecular axes of different orientation relative to the compound crystallographic axes.
Comparison of refractive indices of amorphous and crystalline As2S3
(Institute for Single Crystals, 2009) Miloslavsky, V.K.; Makovetsky, E.D.
Method to calculate refractive index and transparency range dispersion of amorphous As2S3 is proposed. It is based on effective dielectric permittivity models for porous composite media, comparison of glass and crystal density and use of data on refractive index of the crystal. It is shown that the best agreement of calculated and experimental values of refractive index of glass is obtained within the wavelength interval 460-670 nm when using Lorenz-Lorentz formula. It is established that As2S3 glasses possess pores with filling factor q=0.057 submerged to isotropic matrix with approximately two times smaller porosity (qM=0.031).
Dispersion of refractive index in thin films CdI2 and ZnI2
(Institute for Single Crystals, 2010) Yunakova, O.N.; Miloslavsky, V.K.; Kovalenko, E.N.
The refractive index dispersion in thin CdI2 and ZnI2 films has been measured in the wavelength interval 300-1000 nm and processed using the monooscillator model ageeing well with experimental data. The optical permittivity e_unlim of both compounds has been determined using the found parameters of this model, the optical permittivity data have been used in the further analysis of exciton states in CdI2 and ZnI2, in particular, for determination of 1s exciton radius. The found a_ex values are close to the unit cell parameters of the compounds, thus indicating that the excitons in two compounds belong to excitons of the intermediate electron-hole band.
On the nature of photoinduced absorption in photochromic (AgCl)x(CuCl)1-x films
(Institute for Single Crystals, 2005) Yunakova, O.N.; Miloslavsky, V.K.; Gromov, M.S.; Kovalenko, E.N.
Absorption spectrum of photochromic (AgCl)x(CuCl)1-x films has been studied. The intense band of induced absorption in visible region has been established to be a superposition of two bands, namely, that of absorption by silver colloid particles shaped as ellipsoids or chains of spherical particles and absorption band of Cu2+ ions in AgCl.
Optical properties of nanostructures
(Institute for Single Crystals, 2008) Miloslavsky, V.K.; Ageev, L.A.; Makovetsky, E.D.; Maskevich, S.A.
The paper is a brief review of optical properties of nanostructures containing metal nanoparticles. There is a deduction of some simple formulae describing optical spectra of composites containing small particles of various form. Comparison of theoretical and experimental data has been carried out. Conclusions following Mie theory of diffraction on spheres of various diameters and dielectric permittivities are discussed. Various examples of applications of nanoparticles and their influence on surrounding media are given.