The present work is devoted to the investigation of the peculiarities of fluctuations in glass-forming liquids. To justify our reasons we will anlayze the character of molecular light scattering in silicate glass, that was the object of experimental study. Our approach to the problem of fluctuations in glasses and liquids near the glassification point is based on the following general motivations. Highly-viscous and glass-like states of glass-forming liquids are in the metastable region, which correspond to the crystal state of a system in the equilibrium. The behavior of a system is determined by relations between two characteristic times: τ_w(T) and τ_e, where the former is the waiting time for the critical nucleus and τ_e is the time for cooling the system from the melting temperature to the spinodal temperature T_s at the same pressure. If τ_e <(<<) τ_w(T_s) the system smoothly passes to the glass-like state. Here two factors are very important. In metastable region of a system the nuclei of the new phase (crystal) appear. The fraction volume φ(T), occupied by them, depends on the cooling rate. The value of φ is the less the more quick cooling the system is. However, below the spinodal in accordance with thermodynamics the homogeneous states of a system are impossible. The existence of the lasts contradicts the stabilty conditons. From here we conclude that typical glass-like states in a system should be microinhomogeneous. Similar conclusion is confirmed by the results of experimental study of the structure. Now we should note that the strongly anisotropic interaction between nonspyherical molecules of glass-forming liquids leads to considerable coupling between the translational and orientational degrees of freedom in a system. In other words the changes of density is accompanied by the corresponding modulation of molecular orientations. Due to strong increasing the shear viscosity at approaching the glassification point some configurations of the centers of mass and the orientations of molecules froze. More exactyly, only weak thermal deviations of coordinates of molecules from their local equilibrium values are possible. The radical change of the global molecular configuration requires exponentially large time. Thus, the combination of frozen and thermal fluctuations is the distinctive feature of glass-like state of a system. It is necessary to note that different ways of cooling of a system lead to nonequivalent frozen fluctuations.

Effects of compositional fluctuations and interface roughness on the exciton scattering in diluted magnetic semiconductor crystals with quantum wells in an external magnetic field were studied. Broadening of the light reflection, transmission and absorption spectra due to the magnetic impurity concentration and spin projection fluctuations was calculated. The fluctuations of both single and pair impurity center distributions, disc from inclusions as well as destruction of antiferromagnetically coupled pairs by a high magnetic field were taken into account. Calculations were performed for quantum wells (Cd,Mn)Te/CdTe/(Cd,Mn)Te. It was shown, that presence of the fluctuations under study allows to explain the bandwidth value in accordance with experiments. Interesting effect of the external magnetic field induced narrowing of the exciton bandwidth was predicted. Step-like magnetic field dependence of the bandwidth due to antiferromagnetically bounded pair destruction was obtained. These peculiarities in the magnetic field dependence of the exciton bandwidth were explained by the coherent summation of spin-dependent and spin-independent parts of the interaction between the exciton and the defects.

IR spectra of polycrystalline δ-KIO₃ HIO₃ have been studied in the temperature range from 13 to 300 K. A systematic temperature dependent study has been performed for the hydrogen bond stretching and bending vibrations. Features observed in the high frequency region of vibrational spectra of the title crystal are discussed with respect to possible formation of new charge compensating protonic species in the proton sublattice.

We have researched intentionally unalloyed and alloyed by lithium and copper ceramic samples ZnSe with various contents of admixtures. It is discovered that with the increase of admixture contents the electric conductivity of samples is increasing non-proportionally to the increase of concentration. Dependence of the value of conductivity of admixture concentration has the area of the sharp increase of electrical condcutivity of samples on the condition of concentration increase for one order of the value. The discovered particularity of conductivity is explained on the base of the theory of proceeding streaming the lumpy systems. The spectrum of photoluminescence of ZnSe ceramics depends on the nature and concentrations of alloyed admixtures.

In the present, photoluminescence of δ-KIO₃ HIO₃ crystals has been studied for the first time in the temperature range of 4.2-77K. It was shown experimentally that at T=4.2 K the edge of self-absorption band is located near 295 nm. In the luminescence spectra of the title crystal, two bands are found which differ in their spectral position and lifetime. The short-wave luminescence band centered at 367.5 nm. This band appears only in the csae of the crystal excitation by the light with the wavelength that does not fall in the region of self-absorption of the crystal, eg λexc = 340 nm. When the temperature increases from 4.2 to 34 K, the intensity of this band falls down almost to the background value, whereas the position of its maximum remains practically unchanged. The long-wave luminscence band of the δ-KIO₃ HIO₃ crystal with peak position at 410-420 nm and the lifetime of about 1 s is attributed to phosphorescence. This spectrum appears only in the case of excitation within the region of self-absorption of the crystal, eg λ3xc = 275 nm. On the basis of experimental data analysis, the assumption has been made that the short-wave band originates from the emission of excitons located at the defects of the crystal structure, and the long-wave band is related to radiation decay of autolocated bihalide excitons. Possible photoprocesses in the title crystal caused by light absorption of different wavelength are discussed.

Angular dependencies of the Raman modes frequency on direciton of phonon wave vector q in tetragonal gyrotropic crystals TeO₂, ZnP₂, and CdP₂ were investigated and compared. We observed two completely different types of angular behavior of E-doublets splitting in depending on relative contributions of spatial dispersion and long-range Coulomb interaction. The explanation of apparent anomalous dependence of E-doublet 122 cm^-1 splitting on q in TeO₂ is proposed.

Solving the self-consistent volume integral equation, we compute the local susceptibilty, as well as volume-averaged one of a small parallelepipedal particle interacing with a flat substrate. To estimate the measure of nonpointness of a particle, the susceptibility in the particle center is compared with that calculated in the dipole point-like approximation. It is shown that a parameter specifying nonpointness is determined by the difference in the particle and ambient dielectric constant, as well as by measure of deviation of the particle shape from cubic one. Numerical calculations of absorption cross-section carried out for small dielectric particles shw that the substrate effects lead to the low-frequency shift of the spectra and appearance of a low-frequency subsidiary peak.

This paper is devoted to investigations of discontinuous metal films on semicondcutor surface by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Technology of local electrochemical deposition of noble metal nanoparticles on semiconductor substrate is elaborated. It allows to obtain as well isolated Au particles with the 2-50 nm diameter as some chain structures perhaps of fractal type. According to the TEM and AFM data the gold clusters have the form of a truncated spheres surrounded by uncovered microrelief areas of semiconductor. Comparison of these two methods allows to study the morphology of metal coating, and the shape of metal islands, and their sizes. The microrelief of substrate surface, inevitable at used technology of the gold preparation, has been identified. In order to study the effect of both gold island and surface roughness on the optical properties of structures, we performed the reflectance spectra of polarized light measurements at several angles of incidence. Optical reflectance spectra are interpreted by the modified Maxwell-Garnett theory taking into account the pair multipole interaction between the nanoparticles or by the symmetrical Bruggeman's approximation.

This paper presents optical absorption spectra and refractive index dispersion curves of porous anatase thin layers on glass substrate. The results have been measured in the photon energy range 1,5-3,5 eV at room temperature. Estimated samples porosity is about 58 percent in framework of Bruggeman effective medium approximation. Indicatrix of diffusion was measured at 632.8 nm. Defects absorption gives the major contribution into transmitted light losses below the gap in comparison with scattering phenomena. We obtained optical band gaps for both direct -Eg = 3.69 eV and indirect transitions Eg = 3.42 eV. The Urbach tail width 180 meV obtained from the optical absorption measurements agrees with the magnitude of trap depth 185 meV from the conductivity temperature dependencies for the similar anatase nanocrystallines.

A theory of electromagnetic surface wave propagation on a plane superconductor-vacuum interface is presented for superconductor with strong-coupling. The resutls of self-consistent euqation for eneryg of elementary excitations obtined in the framework of modified u-v transformation method.On the basis of a non-local description taknig into account the finite size of the pair-bound state, the linear resopnse tensor is analyzed. Within the framework of semi-classifcal infinite-barrier model the surface waves dispersion relations are the analyztically and numerically calculated for teh case of strong-coupling superconductor.

Interaction of the transition metal salts and polyaniline in the form of a solution has been studied. It was found that addition of some salts to the polyaniline solution gives rise to formation of a precipitates formed have been studied and molecular model of the polyaniline-transition metal ion compelx has been proposed.

The pyroelectric detectors on the basis of systems: thin nickel film--thick lithium niobate substrate, thin molybdenum film--thick lithium niobate substrate and thin titanium film--thick lithium niobate substrate implanted by argon ions as sensitive elements were designed. The optical constants of such systems with film thicknesses of d=15, 20, 30, and 40 nm in the wide spectral range were measured. It is shown that the reflectance of the system thin nickel film--lithium niobate increases and the reflectance of the systems thin molybdenum film--thick lithium niobate substrate and thin titanium film--thick lithium niobate substate decreases owing to the implantation. The influence of ion implantation on the surface structure of such systems is studied by electron microscopy. The optical characteristics and the functional parameters of pyroelectric detectors such as spectral sensitivity, radiation stabilty are researched. The number of advantages of such pyroelectric detectors among other detectors of similar type is found.

Spectroellipsometrical measurements are usually made on smooth surfaces or surfaces with small roughness. Practical needs often demand measuring optical parameters of real details and products. The surface of these dtails and products is not mirror-like, but veyr rough, that is Ra greater than/equal to λ. This work shows possibility of ellipsometrical measurements on very rough surfaces. We proposed the method of ellipsometrical measurement of these surfaces and made investigations for metal rough plates and semiconductor surfaces of the anodized aluminum. The most common method of measurement of spectroellipsometrical parameters is the Beatty method and its different modifications. Therefore it is for this method that we work out our own principles.

The use of spectrophotometric references under conditions that differ from CIE recommended illumination and viewing geometries is possible only if the bidirectional reflectance function is known. One of the materials used for realization spectrophotometric primary transfer standard is milky glass with polished surfaces. A model that describes scattering of light by a similar object is proposed in this study. The comparison between theoretical results and experimental data is carried out. In view of the results of modeling, a perspective of creating a method of goniophotometric calibration of Russian opal glass for any illumination and viewing condition is discussed.

The theoretical analysis of resonant dynamic intermolecular interaction influence on formation of isotropic intramolecular vibrational bands contours in liquids at various temperatures, stipulated by existence of molecules local ordering, has been conducted within the framework of cluster-continuum modle. The new mechanism of isotropic spectral bands narrowing with temperature, observed for some liquids, is offered. This mechanism is stipulated by growing similarity for frequencies of resonant splitting intramolecular vibrational components as structural elements of appropriate spectral bands owing to temperature disording of local molecular surroundings in liquids. On example of liquid methyl iodide the computer analysis of proposed mechanism influence on formation of liquids vibrational spectral function at various temperatures is conducted. The satisfactory consent between results of computer analysis and appropriate experimental data is obtained.

Three methods of effective molecular size evaluation originated from scaled particle theory (SPT) and a method proposed by Dejardin et al are checked by correlation analysis on internal consistency. It was shown that the Dejardin's method looks more attractive than SPT methods for estimation of the molecular radii r. Temperature dependence of r is analyzed from the viewpoint of SPT and compared with data of spectral shift experiments. Temperature shifts of S₁ S₂ spectrum of anthracene dissolved in different solvents are as example of such analysis. In accordance with SPT prediction the estimated values of r decrease with temperature increase only in approximation of neglecting of its out-of-plane core vibrations of anthracene.

Phenanthridine dyes have pronounced mutagenic activity due to their intercalative binding with double-helical DNA. Although the structural significance in the interacalation process of the phenanthridinium chromophore is well established, the role ofits side chains is still under discussion. The comparative analysis of complexation with DNA of phenanthridinium dyes - ethidium bormide (EB) and its two photosensitive analogues: 3-amino-8-azido-5-ethyl-6-phenyl phenanthridinium bormide (EMB) and 3,80diazido-5-ethyl-6-phenyl phenanthridinium chloride (EDC) has shown that they have different affinities of binding with nucleotide sequences in aqueous salt solution. In order to test the role of azido-groups in side chains of EB chromophore on the drug-DNA affinity, the self-association of EB and its two azido-analogues have been studied in this work by one- and two-dimensional 1H-NMR spectrosocpy. Self-association of the aromatic drug molecuels has been studied using concentration and temperature dependences of proton chemical shifts. The equilibrium reaction constants, cooperativity parameters, the limiting values of proton chemical shifts and thermodynamical parameters-enthalpy and entropy of drug self-association have been determined for all the molecular system studied.

This work studies the influence of the electromagnetic radiation of low intesity on the rheologic parameters of water and water solutions of biologically active substance, which plays an important role in energy transforming processes in living organisms. The power spectrum of the thermal fluctuations of the free surface of liquid has been measured using optical heterodyning method which makes it possible to detect the changes in frequency of the light scattered by moving liquid surface. The amplitude, the spectrum of spatial and time frequencies of thermal fluctuations of free surface of a water solution was investigated using optical heteodyning method. The viscosity and the surface tensions in the micro layer of water solution were determined from the obtained results. Water solution was dealt with as a low-viscosity Newtonian liquid in this analysis and was modeled by Navier-Stokes equation and incompressibility equation.

Excitonic states in liquid and solid orientationally disordered solutions are considered. It is shown that collective properties of excitations depend essentially on correlation properites of orientational degrees of freedom of the solution. Specifically, this dependence is exponentially stronger in liquid solutions compared with solid solutions. It is also shown that energy level shift caused by exciton interactions linearly with the concentration of molecules.

Fourier transform IR spectra of flexible biphenyl molecules as well as their 4-n-alkyl-4'-cyanobiphenyl derivatives with 2, 3, 4, 5, 6 and 7 carbon in alkyl chain, all in solid crystalline state in KBr pellet, were investigated. In order to determine and characterize all vibrations in the range of 400-4000 cm^-1, Fourier transform IR spectrosocpy were applied. The different number of bands, their shapes and frequencies for alkyl-cyano-derivatives of biphenyl has been found. But the most essential changes were observed in the range 800-900 cm^-1 and 2700-3000 cm^-1. Few bands have been found in these regino while biphenyl does not display any bands in these two regions. It is shown that the changes observed in the spectra are not directly dependant on the relation of aromatic cyano core and length of the alkyl tail of the molecule.

This paper presents a theoretical study of differential and total light scattering cross-sections in liquid crystals containng small hard macroscopic spherical or cylindrical particles, using the naomalous-diffraction approach. The light scattering is normally governed by director inhomogeneity around teh separate particles. When the particles form a network the scattering is controlled by the director domain structure. We consider the influence of particle shape and size, the type of director anchoring on the particle surface and light polarization. Our principal findings are that: (a) for a so-called 'dipole' director configuration around the particle, the light scattering is predicted to be approximately two orderes of value stronger than for a so-called 'Saturn ring' configuration; (b) incident light polarizred parallel to the scattering plane gives rise to a stronger scattered angular dependnece than light polarized perpendicular to it; (c) when the inclusions are cylindrical the light scattering is relatively stronger at lwo scattering angles than when the inclusions are spherical; (d) for a particle network, the nature of the network domain orientational distribution influences the intenstiy of light scattering, but has little effect on its angular dependence.

Ionic metal-organic liquid crystals are calling the growing attention of researches in view of variety of their optical, electro-optical and nonlinear optical properties. The typical for this class of mesogenes are metal alkanoates, the structure of which corresponds to smectic A. Salts of alkanoate cacids being mixed with water at room temperature form ionic lyotropic liquid crystals (ILLC), the mesophase structure of which is analogous to that of a thermotropic smectic A. In this work we investigated absorption, luminescence spectra, electrooptical and nonlinear optical properties of ILLC doped with different ionic polymethine dyes. Obtained spectral and optical characteristics of doped ILLC allowed the holography grating recroding. ELectrical investigation has shown that in ILLC and double electrical layer took place near the electrodes. The charge transfer in this area can be described by the Schottky emission through a thin dielectric layer. The comparison with usual liquid crystals shows that the conductivity thin ILLC is more than by three orders higher. Specific spectral, electrical and optical properites of pure and doped ILLC were explained due to the peculiarties of interionic interaction.

The conformational mobility and structure of 4-pentyl-4'-cyanobiphenyl (5CB) in liquid and liquid crystal states have been investigated by methods of IR spectroscopy. IR absorption spectra are measured in the temperature range of 297-425 K in 400-4000 cm-1 spectral region. The IR spectra are modeled for the conformers of 5CB which differ in the orientaiton of the alkyl radical wiht respect to the biphenyl fragment and of the benzene rings with respect to one another. It is found that the temperature changes of IR spectra are determined by the molecule conformational mobility of 5CB. From the analysis of the spectra, we determined the most probable configurations of the molecules which were realized in the sample within the studied temperature interval.

The results of investigation of polymorphism and mesomorphic states of fluorinated derivatives of alkylcyclohexanecarboxylic acids nFACHCA and new results for n=4, 7 are discussed. The methods of vibrational spectroscopy have been used. The samples were investgiated in the 290-500 K temperature range. The spectra were recorded in the range of 400-4000 cm^-1. The frequencies of normal modes and IR band intensities are calculated for conformers of H-bonded complexes with varioius orientations of fluoroalkyl radical and carboxylic group relative to the rest of the molecular compelx. The polymorphism of the nFACHCA is conformational. The influence of H-bonds on dynamics of H-bonded complex, polymorphic crystalline modification and mesophase formaiton was determined. The transitions solid crystal-liquid crystal-isotropic liquid and soution are accompanied by H-bond system reconstruction: the dimers, associates, chain associates and monomers appear.

We calculated the scattering of light by composite anisotropic particles embedded in an isotropic matrix by using the T-matrix ansatz. The model scatterer is assumed to consist of a small central isotropic particle coated by a much larger region in which the optical tensor is radially anisotropic. We determine the region of validity of Rayleigh-Gans approximation (RGA) by comparing approximate values of the scattering cross-section and the dispersion index with the results computed from the exact solution. Both of the scatterers with isotropic and radially anisotropic annular layers have been studied. Our results show that RGA for anisotopic scatterers gives less accurate estimates than when the scatterer is isotropic. In the small particle limit, we have calculated the value of dielectric contrast of effective isotropic sactterer as a function of anisotropy parameter and the layer thickness. We have found that averaging the dielectric tensor over angles gives correct results only if the anisotropy parameter is small.

UV light influence on the surface potential φs of poly(vinylcinnamate) (PVCN) layers widely used for liquid crystal (LC) photoalignment is investigated. In case when PVCN film is spin coated on the ITO electrodes the surface potential changes under irradiation in both PVCN aligning film and ITO coating. The measured increment of the surface potential changes under irradiation in both PVCN aligning film and ITO coating. The measured increment of the surface potential Δφs=400 mV is mainly cuased by the photoconductivity of ITO electrodes, whereas the part caused by PVCN substrate is at least one order of magnitude lower. The relaxation time of Δφs for the ITO-PVCN coatings was estimated to be about 1 h. The induced potential may substantially modify dielectric properties of the aligned LC layers and its anchoring characteristics when the freshly irradiated substrates are used. On the contrary, this influence is weak when the substrates are irradiated several hours before the use for LC alignment.

Director reorientation threshold in the field of electromagnetic wave in round cylindrical metallic waveguide loaded with nematic liquid crystal is theoretically studied. The dependence of threshold on the frequency and type of electromagnetic wave in waveguide as well as director anchoring energy with waveguide surface is analyzed.

In this work, on the example of odd-numbered normal paraffins and α-olefins we propose a mechanism which explains the temperature dependence of the amgnitud eof Davydov splitting Δυ_1,2 of the bands of scissoring and rocking vibrations of methylene chains of long-chain compounds with frequencies 1456 and 720 cm^-1, respectively. This mechanism is connected with damping of the intramolecular vibrational excitons in crystals due to their interactin with orientational defects of the lattice which emerge as a result of excitation of librational-rotational degrees of freedom of organic molecules in the region of the phase transition of order-orientaional disorder type. Good agreement was observed bewteen theoretical and experimental results.

Macroscopical properties of some induced cholesteric compositions based on 4-pentyl-4'-cyano derivatives of biphenyl and phenylcyclohexane as host phases have been investigated. The series of N-arylidene derivatives of (S)-1-phenylethylamine with varied both rigid moiety of the N-arylidene fragment and terminal substituent was used as chiral dopants. The influence of the chiral dopant molecular structure as well as of physical properties of the host phases used on the helical twisting power, the temperature dependence of the induced helical pitch and the N* mesophase thermal stability has been characterized. It has been concluded that the distinctions in properties of the LC systems containing the OCH₂ and COO linking groups are caused by their different conformational states.

Concentration dependences of dielectric permittivity are studied in binary mixtures of liquid crystal with large value but different sign of dielectric anisotropy and in mixtures of highly polar 8OCB with non-mesogenous and non-polar stearic acid. Positive derivatives of the real part of ε from the additive values in a wide concentration range in observed both in different liquid crystalline and isotiprc phases. Results obtained are considered in comparison to previous works and described in terms of molecular packing and dipole interactions effects. Possible applications of such systems and their unconventional dielectric properties is discussed.

We report on theoretical study of optical singularity birth in a wave front of light beam with stigmatic and astigmatic Gaussian profile with intially smooth wave front passing through a homeotropically aligned nematic liquid crystal (NLC) cell. When a linearly polarized astigmatic Gaussian light beam illuminates the cell, the light induced Frederick's transition can be observed. Strong director anchoring at the cell walls is assumed. Ritz's variational method is used, i.e. the profile of director reorientation is considered to be similar to astigmatic Gaussian profile. Parameters of the trial function are calculated numerically. The threshold intensity of light beam is appeared to increase with increasing of asymmetry of the beam under the constant value of laser beam area and cell thickness. Utilizing the Huygens-Fresnel principle and geometrical optics approximation we calculate the amplitude distribution in space for different distances from the cell. It is obtained that in the case of stygmatic Gaussian beam incidence on NLC cell the circular edge dislocation is born.

The structures of optical neural nets (NN) based on new matrix-tensor equivalental models (MTEMs) and algorithms are described in this article. MTE models are neuroparadigm of non-iterative type, which is a generalization of Hopfield and Hamming networks. The adaptive multi-layer networks, auto-associative and hetero-associative memory of 2-D images of high order can be built on the basis of MTEMs. The capacity of such networks in comparison with capacity of Hopfield networks is increased. The results of modeling show that the number of neurons in neural network MTEMs is 10-20 thousand and more. The problems of trailing of such networks, different modifications, including networks with double adaptive-equivalent autoweighing of weights, organization of computing process in different modes of network are discussed. The basic components of networks: matrix-tensor 'equivalentors' and variants of their realization on the basis of liquid-crystal structures and optical multipliers with spatial and time integration are considered. The efficiency of proposed optical neural networks on the basis of MTEMs is evaluated for both variants on the level of 10⁹ connections per second. Modified optical connections are realized as liquid-crystal television screens.

The absorption spectra of the solutions of polysilanes like poly(methylphenylsilane) and poly(dihexylsilane) with various acceptors were investigated. It is shown that several new broad bands in visible reigon arise in the absorption spectra of polysilanes with addition of acceptors, which is accompanied by changes in the color of the solutions. These new bands are attributed to formation of CT-complexes between σ-donor and π-acceptor, i.e., polysilanes with admixture of acceptors can be used both as transport layers and photogeneration ones. The possible nature of the structure of the absorption bands of these CT-complexes is discussed.

The scattering spectra of low-absorptive disperse media are not much researched. It is stipulated by the same difficulties: in experiments, the theoretical investigations had low precision and some errors and the most precise Monte-Carlo method until quite recently was difficult to use in that aim in view of the large time expenses. However, that theme required investigation since the scattering spectra are very informative and make it possible to describe the internal structure of the studied object. It is important in researches of biotissues when the scattering spectra are the means of effective non-invasive diagostics. In our study the system of spherical particles which sizes are comparable with radiation wavelength that then applied to the tissue of eye lens, the internal parameters of which were changing depending on the pathology cases were modeled. And the results of theoretical investigations of scattering spectra of these objects obtained by the Monte-Carlo simulation are presented.

The absorption, fluorescence and phosphorescence of the carbazole-containg polymers with phosphore groups in the main chain of two types and without spacer were studied. It was shown that spectral properties of pf₂-sep polymer are connected mainly with optical transitions in individual carbazole chromophores. The optical properties of pf₂-conj polymer are rather different comparative to the pf₂-sep. That is caused by perturbation carbazole groups electron system by phosphor-groups and influence carbazole groups each other. This perturbation takes place under special relative geometrical displacement of carbazole and phosphor groups.

Recently we have shown that DNA molecules extracted from epididymis of the Wistar male rats exposed to low doses of gamma radiation interact with some pyrimidine nucleosides. The bindign affinities of NUC to control DNA molecules are unessential. Comparing the UV melting curves for the various DNA sammples we show that observed differences are related to conformational chagnes in the DNA double helix. The samples of the damaged DNA have been obtained by partial denaturation of the calf thymus DNA in the salt-free aqueous solutions. The level of DNA damages in the model DNA smplase depends on the DNA concentration. It was shown that damages in the DNA molecules lead to changes of the melting curves of DNA-NUC mixtures that are similar to those for the DNA samples extracted from irradiated tissues. ALso it has been found that the binding mechanisms to cytosine arabinoside and 6-azacytosine to DNA molecuels having modifeid secondary structures are different.

In the paper, molecules formed on the basis of the noble-gas monohalogenides are considered. ELectron and rotatinal structure of excimer molecules is considerd. Occurrence of some specific levels, conditioned by a small coupling energy in the ground state of molecules of the noble-gas monohalogenides is discussed. Main attention is paid to the electron and rotational structure of XeCl and XeF molecules.

Structure of stimulated emission spectra of noble gas monohalogenide moleculea lasers is considered. Spectrum of KrF lasing on bound-to-free transitions is reported. Fine structure of stimulated emission spectra of molecules with shallow potential well in the ground state is considered by the example of XeCl and XeF molecules. The structure is due to rotations in XeCl and XeF. Influence of the active medium parameters on the structure of XeF molecule stimulated emisison spectrum structure as well as spectral performances of emission of XeF laser pumped by powerful electron beam and pulsed electric discharge are considered. The nature of the lasing spectrum in the regin near 350 nm is discussed. The report is based mainly on the authors' studies.

The advantages of a polyurethane matrix over other polymers, which are widely used as active media for dye lasers, are analzyed. This matrix exhibits the photostability, service life, radiation resistance, conversion efficiency, and homogeneity of the dye distribution that surpass these properties for active media based on polyurethane acrylate, which has close physical and operation properties. These advantages result not only from the milder polymerization conditions but also from a lower probability of the formation of ion pairs and dye aggregates. A substantial suppression of these processes in polyurethane is explained by its greater polarity and solvation ability compared to polyurathane acrylate.

It is shown that the motion of a focal region in self-focusing liquids changes the radiation frequency of an anti-Stokes component of stimulated Raman scattering. The displacement of the anti-Stokes component frequency relatively to an exact Raman resonance is due to the implementation of amplitude-phase matching conditions, namely, the phase coordination has to carry out in the vicinity of the moving point where the amplitude of polarization has a maximum.

The transmission spectra of inversionless amplification are investigated. Propagation of a weak probe optical beam through a three-level medium pumped with a microwave strong beam is numerically modeled. Three various schemes of transitions under the conditions providing the amplification of the probe field without inversion are taken to calculate the atomic polarization, which enters the paraxial wave equations. Diffraction and self-action ofbeams due to nonlinear absorption and refraction are properly taken into account. These effects together with linear absorption and refraction form a complex distribution of gain across the beams. As a result the amplified beam acquires ring transverse patterns and slight asymmetry in the frequency characteristics.

For aromatic fluorophores embedded into different rigid and highly viscous media with low structural order the spectroscopic properties do not conform to classical rules. The fluorescence spectra can depend on excitation wavelength, and the excited-state energy transfer, if present, fails at the 'red' excitation edge. These Red-Edge effects are observed due to the existence of excited-state distribution of fluorophores on their interaction energy with the environment and the slow rate of dielectric relaxations. In these conditions the site-selection can be provided by variation of energy of illuminating light quanta, and the behavior of selected species can be followed as a function of time and other variables. These observations foudn extensive application in different areas of research: colloid and polymer science, photophysics and molecular biophysics. Site-selection effects were discovered for electron-transfer and proton-transfer reactions if they depend on the dynamics of the environment. In this report we concentrate on fluroescence of 3-hydroxyflavone derivatives as the probes that exhibit the excited-state proton transfer reaction. The studies in polymer films, phospholipid membranes and in complexes with proteins allow characterizing the static and dynamic disorder in these systems.

Photorefractive material have certain prospects for usage in coherent-optical schemes of the optical signal processing. Their values in this aspect are non-linear resopnse to the intensity of signal and variety of temporal characteristics of record and erasure of images, including holographic ones. In this presentation, questions connected with usage of photorefractive crystals in the holographic correlator with the associative resopnse to fragments of recognized signal were investigated. Particularity of the correlator scheme consists in getting response in the manner of the signal under investigation itself. Due to it, the level of signal identification increases under its associative processing. Use of spatial modulator of signal wave front and photorefractive crystals in the scheme allows to vary a structure of angular spectrum of recorded images when writing the holograms. In certain limits, it gives a possibility to control sensitivity of image as to change of structure of fragments which restore a hologram, keeping stable associative response.

This report presents both the results of experimental investigation of the features of sterilization by plasma DC glow discharge: a) dependencies of the efficiency of plasma sterilization on discharge parameters; b) ratio between main sterilization factors, and the results of numerical simulation of component composition.

Particularly pure samples of titanium dioxide with a different crystalline structure and a different construction of TiO₂ polycrystaline particles which were produced by thermal hydrolysis of TiCl₄ hydrochloric acid solutions, were studied by methods of IR and Raman spectroscopy. The assignment of IR and Raman spectral bands to vibrations of different symmetry types has been performed. In accordance with positions and half-width of Raman lattice vibrational band 'ν=143 cm^-1'. The stoichiometric composition estimation of TiO₂ different crystalline phases has been carried out according to data obtained about the position and half-width of the lattice Raman vibrational band. The intensity and frequency of IR bands in the region of 1250-900 cm^-1 were shown to be sensitive to a type of TiO₂ crystalline composition and to the physically adsorbed water content.

Internal Stark effect in electronic spectra is the effect that is observed when the electronic bands shift udner the influence of promixal charges. In order to study the possible involvement of this effect in modulating the intramolecular proton transfer reactions in the excited state, we designed and studied several derivatives of 3-hydroxyflavone. They include the species containing neutral and positively charged substituents in 6 position of chromone ring. These compounds were studied in solvents of different polarities. In these experiments the shifts of both normal and tautomer flurosence bands are clearly observed in a manner predicted by Stark effect theory. In addition, a dramatic effect of suppression by introduced charge of intramolecular excited-state proton transfer was observed.