The vibrational IR and Raman spectra of the adamantane-containing compound of 3-(adamantan-1-yl)-4-ethyl-1-[(4-phenyl-piperazine-1-yl)methyl]-1H-1,2,4-triazole-5(4H)-thione, promising for drug design, were examined in the ranges 3200-650 and 3200-150 cm^-1. The UV/Vis spectrum of the solution of the compound in ethanol was measured in the range 450-200 nm. On the basis of full geometry optimization within the framework of density functional theory (DFT) in B3LYP/cc-pVDZ approximation, the equilibrium configuration of the molecule was determined and IR and Raman vibrational spectra were calculated. Based on this, the experimental vibrational IR and Raman spectra were interpreted and the biological activity indices were predicted. The UV/Vis spectrum of the title compound was simulated at the time-dependent DFT/CAM-B3LYP/cc-pVDZ level with and without solvent effects and at the ab initio multi-reference perturbation theory XMCQDPT2 level. It is established that the simulation of the UV/Vis spectrum using multi-reference XMCQDPT2 approximation, in contrast to the single-reference DFT method, very successfully agrees with the experimental data, which is probably a consequence of intramolecular charge transfer.

Within the framework of the method of additive modeling of the low resolution microwave spectra of the heteroisomeric molecules of substituted hydrocarbons, the theoretical models of low resolution microwave spectra of ethanethiol and propanethiol molecules were produced for the 0-2 THz frequency range with spectral maximums at 465±20 and 240±20 GHz, respectively. More precise calculations at the narrow frequency band of the above-mentioned frequency ranges were provided using the spectral line half-width values 1.5, 0.8, and 0.5 МHz, modeling the conditions of different layers of the Earth’s troposphere. This permitted to specify the most intensive generating extrema of the low resolution spectra of the investigated species of ethanethiol and propanethiol as 486±5, 446±5, 436±5 and 257±5, 239±5, 234±5 GHz, respectively. The different aspects of the application of the obtained results were discussed.

For the case of homomorphic chromophores, the localization of the 0-0-transition n₀ is defined in a separate electronic transition cross-section spectrum s(n) by the extremum (¶j/¶n = 0) of the relation [s(n)/n]exp(mhn/2kT) = j(|n - n₀|) (“-“ and n > n₀ for absorption,“+” and n < n₀ for emission). It holds for the dipole Frank-Condon transition under conditions of thermal distribution on state sublevels. If the spectrum is formed by polymorphic chromophores, it constitutes of the sum of partial inputs of the separate chromophores with different n_i0. So, the area of the extremum is distorted, the extremum can even disappear and the distortions indicate chromofore polymorphism. Examples are given for the distortion from absorption, fluorescence, and phosphorescence spectra

The CLRS detection characteristics of acetone dissolved in transformer oil were analyzed. Raman spectral peak at 780 cm^-1 was used as the characteristic spectral peak for qualitative and quantitative analyses. The effect of the detection depth and the temperature was investigated in order to obtain good Raman signals. The optimal detection depth and temperature were set as 3 mm and room temperature. A quantitative model relation between concentration and the Raman peak intensity ratioI₇₈₀/I₈₉₃ was constructed via the least-squares method. The results demonstrated that CLRS can quantitatively detect the concentration of acetone in transformer oil and CLRS has potential as a useful alternative for accelerating the in-situ analysis of the concentration of acetone in transformer oil.

The annealing temperature dependence of luminescence properties of silver (Ag) exchanged zeolites Y and A was studied. It was found that the absorbance and excitation/emission bands are strongly affected by the thermal treatments. With increase in annealing temperature, the absorbance of Ag in zeolite Y increases at first and then decreases. However, the position of the excitation/emission band in zeolite Y was found to be insensitive to the annealing temperature. In contrast, the excitation/emission bands in zeolite A are particularly sensitive to the annealing temperature. The difference of such temperature dependence in zeolites Y and A may be due to the different microporous structure of the two minerals. Moreover, the fact that this dependence is not observed in Ag-exchanged zeolite Y is likely to be due to the difficulty in dehydration of zeolite Y in air or due to the weak Ag⁺-Ag⁺ interaction in zeolite Y.

Difference in spectral and fluorescent properties of BTA-1C cation in protic and aprotic solvents was found. It has been shown that, for the dye solutions in long-chain alcohols, viscosity is the dominant factor which determines the dynamics of intramolecular charge transfer in the excited state of BTA-1C. In the case of aprotic solvents, we found correlation of the rate of twisted intramolecular charge transfer (TICT) process with the solvent relaxation rate k_TICT ~ 1/t_S.

The experimental spectra of the luminescence and selective emission (SE) of 10 at.%Er³⁺: YAG and 1 at.%Er³⁺ :CaF₂: single crystals and Er₂O₃ polycrystal under laser and laser thermal excitation of the multiplets of the Er³⁺ ion electron shell are compared. Luminescence spectra under resonant excitation are determined by the relaxation of the population of the multiplets with proper radiative and nonradiative probabilities. The form of the SE spectra is determined by the thermal population of the multiplets and the probabilities of radiative transitions. The SE band at λ ≈ 800 nm (⁴I_9/2→⁴I_15/2) is an indicator of the high temperature thermal emission of Er³⁺ ions. The absence of this band in the luminescence spectra is explained by the small lifetime of the level τ(⁴I_{9/ 2} )= 53 ns at T = 300 K.

А theory of the two-photon transition has been developed for the case when the frequencies of absorbed and emitted radiation are in resonance with transitions on one intermediate level of the medium. The conditions are determined for which these resonant two-photon transitions can play a major role.

The radiation effect on the light absorption by potassium-alumina-borate glasses with iron oxide additives of various concentrations was studied at different sample thicknesses. It was shown that, in contrast to samples of small thickness (1 mm), a bleaching effect was observed in samples with a thickness of 8 mm. A possible mechanism of the revealed bleaching effect associated with the formation of nanostructured units is considered.

Influence of g-irradiation on the optical properties of a polyimide film and its polymer compositions with fillers from a dispersed powder of a high-temperature superconductor ҮBa₂Cu₃O_6.7 (YBaCuO) with a concentration of 0.05, 0.10 and 0.50% by weight was studied. It was established that γ-irradiation with a dose up to 600 kGy does not affect the transparency of polyimide films in the visible region of the spectrum. However, at irradiation doses of 250 and 600 kGy, a weakly expressed fine structure appears in the spectra of polyimide films in the range 220-300 nm, due to the contribution of the resulting diene structures to the optical transmission and the increased content of oxygen atoms. The YBaCuO filler and γ-irradiation cause the polyimide transition from the amorphous state to the crystalline state, which is manifested in a sharp change in the spectrum in the range of ~2.3-3.9 eV. A significant increase in the extinction coefficient was found in the composite containing 0.50% by weight of the filler that is associated with an increase in the radius of action of structurally active fillers on the macromolecules of the matrix.

Stimulated emission, optical properties, and structural characteristics of non-irradiated and proton-irradiated Cu(In,Ga)Se₂ thin films deposited on soda lime glass substrates using co-evaporation of elements in a multistage process were investigated. X-ray diffraction analysis, scanning electron microscopy, X-ray spectral analysis with energy dispersion, low-temperature photoluminescence, optical transmittance and reflectance were used to study the films. Stimulated emission at low temperatures of ~20 K was found in non-irradiated and proton-irradiated Cu(In,Ga)Se₂ thin films upon excitation by laser pulses of nanosecond duration with a threshold power density of ~20 kW/cm². It was shown that the appearance and parameters of the stimulated emission depend strongly on the concentration of ion-induced defects in Cu(In,Ga)Se₂ thin films.

Porcelain identification according to the material appearance (solid, soft and bone) is reduced to a system of classification functions. Classification functions are constructed on the basis of the interrelation between the intensities of the luminescence bands of the optically active impurity Fe³⁺ , Mn²⁺ centers, molecular (UO₂)²⁺ center, and intrinsic defects O^* (oxygen center). Porcelain differing on raw materials and conditions of calcination has different combination of the intensities of bands of optically active centers.

The effect of nitrogen defects in monocrystals of natural and synthesized diamond on the position and width of the fundamental Raman band has been investigated. The samples containing main types of the nitrogen defects in diamond lattice at the impurity content of 1-1500 ppm have been taken for the study. Based on the analysis of parameters of the Stokes and anti-Stokes components in Raman spectra of the crystals that are placed in a cell with distilled water to minimize the influence of heating by exciting laser radiation, the effect of the nitrogen impurity presence in the crystalline lattice of diamond has been exhibited. It is shown that an increase of the nitrogen impurity content in the crystals within the studied concentration range results in the Raman band broadening from 1.61 to 2.85 cm^{- 1} and the maximum shifting to the low-frequency region from 1332.65 to 1332.3 cm^{- 1} . The observed effect value is directly proportional to the concentration of impurity atoms and depends on the form of the impurity ingress into the diamond lattice. It has been found that the change in the position and half-width of the fundamental Raman band for diamond is consistent with the magnitude of the distortions of the crystalline lattice parameter due to the presence of impurity defects and obeys the Gruneisen law.

Using UV and visible spectroscopy, atomic force microscopy, and the method of dynamic light scattering, the growth dynamics and the size distribution of Ag particles (NPs) in the polyvinyl alcohol (PVA) composition, PVA film, and aqueous sol were studied. The hypsohromic shift of the surface plasmon absorption band of Ag NPs, when changing from the PVA composition to the film, has been measured. The magnitude of the shift is 55 nm. The dynamics of Ag particles formation and the particle size have been shown to be highly dependent on the UV irradiation, ultrasonic action, and PVA concentration. Thus, it has been established that UV irradiation accelerates Ag NPs formation in the presence of reducing agents and destroys the formed nanoparticles in case of the lack of the reductant. Partial Ag NPs destruction occurs under the influence of ultrasound, while, after UV irradiation, the ultrasound action leads to the reduction of Ag ions on the clusters.

Doped nanodiamonds, synthesized at high pressure and high temperature (HPHT technique) and by chemical vapor deposition from gas phase (CVD technique), were studied by the Raman and fluorescence spectroscopy techniques. For the CVD diamonds, a significant (hundredfold) increase in the fluorescence intensity of the silicon-vacancy centers, normalized to the volume of the probed material, was observed at the increase in size of the synthesized diamond particles from 150 to 300 nm. Graphitization temperature, significantly smaller than for detonation nanodiamonds, was established for the boron-doped HPHT nanodiamonds under heating in air.

The intensity of spectral lines Al I 309.4 nm, Al II 358.7 nm, Mg II 279.6 nm, Ti II 323.6 nm of the main clay components were studied depending on the position of a sample with respect to the focus of the optical system, when the samples are exposed to radiation of the Nd³⁺ :YAG laser operating in a single-pulse mode. The allowable intervals of positioning the sample relative to the focus of the optical system (positive and negative defocusing) are determined, at which the reproducibility of the intensity values of the spectral lines of the samples of red and white clay do not practically change. It is shown that the position of the sample relative to the focus of the optical system should lie in the interval ΔZ ~ ±1.5 mm at the optimum laser pulse energies for the spectral lines under study. The radiation flux density for various laser pulse energies and distances from the focus to the sample has been calculated. It has been experimentally shown that the reduction of the radiation flux density leads to a decrease in the intensity of the analyzed spectral lines.

Hyperspectral imaging (HSI) has been demonstrated to provide a rapid, precise, and noninvasive method for cancer detection. However, because HSI contains many data, quantitative analysis is often necessary to distill information useful for distinguishing cancerous from normal tissue. To demonstrate that HSI with our proposed algorithm can make this distinction, we built a Vis-NIR HSI setup and made many spectral images of colon tissues, and then used a successive projection algorithm (SPA) to analyze the hyperspectral image data of the tissues. This was used to build an identification model based on linear discrimination analysis (LDA) using the relative reflectance values of the effective wavelengths. Other tissues were used as a prediction set to verify the reliability of the identification model. The results suggest that Vis-NIR hyperspectral images, together with the spectroscopic classification method, provide a new approach for reliable and safe diagnosis of colon cancer and could lead to advances in cancer diagnosis generally.

Raman spectra and ultraviolet-visible absorption spectra of four different geographic origins of radix astragali were collected. These data were analyzed using kernel principal component analysis combined with sparse representation classification. The results showed that the recognition rate reached 70.44% using Raman spectra for data input and 90.34% using ultraviolet-visible absorption spectra for data input. A new fusion method based on Raman combined with ultraviolet-visible data was investigated and the recognition rate was increased to 96.43%. The experimental results suggested that the proposed data fusion method effectively improved the utilization rate of the original data.

A sensitive, rapid, and simple flow-injection chemiluminescence (FI-CL) technique is described for determining cefradine in human urine and capsule samples at the picogram level. The results show that cefradine within 0.1-100.0 nmol/Lquantitatively quenches the CL intensity of the luminol/sulfobutylether-β-cyclodextrin (SBE-β-CD) system, with a relative correlation coefficient r of 0.9931. Subsequently, the possible mechanism for the quenching phenomenon is discussed in detail using the FI-CL and molecular docking methods. The proposed CL method, with a detection limit of 0.03 nmol/L (3σ) and relative standard deviations <3.0% (N = 7), is then implemented to monitor the excretion of cefradine in human urine. After orally administration, the cefradine reaches a maximum value of 1.37 ± 0.02 mg/mL at 2.0 h in urine, and the total excretion is 4.41 ± 0.03 mg/mL within 8.0 h. The absorption rate constant k_a, the elimination rate constant k_e, and the half-life t_{1/ 2} are 0.670 ± 0.008 h^{- 1} , 0.744 ± 0.005 h^{- 1} , and 0.93 ± 0.05 h, respectively.

The interaction of the groove binding compounds - peptide antibiotic netropsin and fluorescent dye (bis-benzimidazole) Hoechst 33258 - with the double-stranded DNA and synthetic double-stranded polynucleotide poly(rA)-poly(rU) has been studied by spectrophotometry. The absorption spectra of these ligand complexes with the nucleic acids have been obtained. Spectral changes at the complexation of individual ligands with the mentioned nucleic acids reveal the similarity of binding of each of these ligands with both DNA and RNA. Based on the spectroscopic measurements, the parameters of netropsin and Hoechst 33258 binding with DNA and poly(rA)-poly(rU) - K and n, as well as the thermodynamic parameters DS, DG, and DH have been determined. It is found that the binding of Hoechst 33258 with both nucleic acids is accompanied by a positive change in enthalpy, while in the case of netropsin the change in enthalpy is negative. Moreover, the contribution of the entropy factor to the formation of the complexes is more pronounced in the case of Hoechst 33258.

A novel asymmetrical squarylium-dye-based dual signaling probe was synthesized and found to exhibit colorimetric and fluorescent properties on selective binding towards Fe³⁺ in ethanol/water (4:1, v/v) solution. The binding constant was determined to be 7.69×10² M^-1, and the detection limit of SQ was 9.158×10^{- 6} M. Most importantly, the 1:2 stoichiometry of the host-guest complexation was confirmed by Job’s method. Moreover, the high sensing ability of the receptor towards Fe³⁺ was also investigated by the electrochemical technique.

The most probable ways to significantly increase the sensitivity of spectroscopic methods for detecting and measuring trace concentrations of greenhouse gas molecules in the atmosphere are considered. The basis of the proposed methods is the addition of light flows of a set of spectral components of a given molecule on a single photodetector by using the transmission spectrum features of devices using the effects of multipath interference.

The photon propagator describing the light interaction with a monolayer of the metal particles (island film) has been calculated within the framework of the coherent potential approximation. It is shown, that the displacement of the maximum frequency of the dipole surface plasmon for a monolayer particle relative to the analogous frequency of the plasma resonance of an isolated particle is not the only manifestation of the influence of neighbors. The influence of the neighboring particles also leads to a bimodal structure of the plasmon resonance spectral line. The possibility of the appearance of a fine structure of the spectral lines of the plasmon resonances is predicted.

The original Drude model, proposed over a hundred years ago, is still used today for the analysis of optical properties of solids. Within this model, both the plasma frequency and quasiparticle scattering rate are constant, which makes the model rather inflexible. In order to circumvent this problem, the so-called extended Drude model was proposed, which allowed for the frequency dependence of both the quasiparticle scattering rate and the effective mass. In this work we will explore an alternative approach to the extended-Drude model. Here, one also assumes that the quasiparticle scattering rate is frequency dependent; however, instead of the effective mass, the plasma frequency becomes frequency dependent. This alternative model is applied to the high T_c superconductor Bi₂Sr₂CaCu₂O_{8+ δ} (Bi2212) with T_c = 92 K, and the results are compared and contrasted with the ones obtained from the conventional extended Drude model. The results point to several advantages of this alternative approach to the extended Drude model.

The radiation decomposition of water in a nano-ZrO₂+nano-SiO₂+H₂O system at T = 300 K under the action of gamma-radiation is studied by Fourier-transform IR spectroscopy. It is shown, that water adsorption in Zr and Si nanooxides happens by the molecular and dissociative mechanisms. Intermediate active products of the radiation-heterogeneous water decomposition are registered including Zr and Si hydrides, hydroxide groups. It is shown that changes in the ratio of ZrO₂ and SiO₂ nanopowders result in a decrease of the radiation-catalytic activity comparing to the initial ZrO₂.