Showing papers in "Optics and Spectroscopy in 2010"
TL;DR: In this paper, the absorption and transport scattering coefficient spectra were calculated by the inverse adding-doubling method using a Cary-2415 spectrophotometer in the spectral range 370-2500 nm.
Abstract: Optical characteristics of human sclera are experimentally studied. Experiments are performed in vitro on a Cary-2415 spectrophotometer in the spectral range 370–2500 nm. Based on the measured diffuse reflection and total transmission spectra, the absorption and transport scattering coefficient spectra are calculated by the inverse adding-doubling method.
44 citations
TL;DR: In this article, the authors studied the infrared spectrum of intact human tooth enamel and dentine in the range of 0.26-10 μm using submillisecond laser pulses.
Abstract: We studied the absorption spectrum of intact human tooth enamel and dentine in the range of 0.26–10 μm. We present the infrared absorption spectra of destruction products of human tooth enamel and dentine by submillisecond laser pulses on a crystal of yttrium-scandium-gallium garnet, activated by chrome and erbium ions with a wavelength of 2.79 μm. We discuss the effect of water spraying on the mechanism of laser ablation and the infrared absorption spectra. We report for the first time transformations observed in the absorption spectra of human tooth enamel in the wavelength range of 2.5–3.5 μm under its heating to +700°C.
36 citations
TL;DR: In this article, the effect of photobleaching in noninvasive measurement of the Raman spectra of light used in determining the carotenoid concentration in human skin can be used to increase measurement accuracy.
Abstract: It was shown experimentally that the effect of photobleaching in noninvasive measurement of the Raman spectra of light used in determining the carotenoid concentration in human skin can be used to increase measurement accuracy. Increased accuracy occurs as a consequence of a decrease in the measurable Raman spectra of the wideband fluorescent background intensity when a sample is irradiated by laser radiation. Furthermore, it was demonstrated that, for the spectra of skin from nine volunteers, the fluorescent background intensity can be decreased on average by a factor of 1.4, which leads to an increase in the signal-to-noise ratio for Raman lines of skin carotenoids by a factor of 1.2 on average. The kinetics of photobleaching of humans can be described by biexponential decay with a correlation coefficient close to unity, which agrees with the presented theoretical calculations.
35 citations
TL;DR: In this paper, the behavior of the skin of a laboratory rat under the action of an aqueous solution of glycerol is studied ex vivo and in vivo, and it is found that the collimated transmission coefficient of ex vivo skin samples increases by a factor of 20-40-fold depending on the wavelength in the studied spectral range, and the diffuse reflection coefficient of skin in vivo decreases on the average by 16%.
Abstract: The behavior of optical parameters of the skin of a laboratory rat under the action of an aqueous solution of glycerol is studied ex vivo and in vivo. It is found that the collimated transmission coefficient of ex vivo skin samples increases by a factor of 20–40-fold depending on the wavelength in the studied spectral range, and the diffuse reflection coefficient of skin in vivo decreases on the average by 16%. The results presented can be useful for many methods of laser therapy and optical diagnostics of skin diseases and localization of subcutaneous neoplasms.
32 citations
TL;DR: In this article, the authors reported experimental results of two room-temperature single photon sources with definite polarization based on emitters embedded in either cholesteric or nematic liquid crystal hosts.
Abstract: We report experimental results of two room-temperature single photon sources with definite polarization based on emitters embedded in either cholesteric or nematic liquid crystal hosts. In the first case, a cholesteric 1-D photonic bandgap microcavity provides circular polarization of definite handedness of single photons from single colloidal semiconductor quantum dots (nanocrystals). In these experiments, the spectral position of the quantum dot fluorescence maximum is at the bandedge of a photonic bandgap structure. The host does not destroy fluorescence antibunching of single emitters. In the second case, photons with definite linear polarization are obtained from single dye molecules doped in a planar-aligned nematic liquid crystal host. The combination of sources with definite linear and circular polarization states of single photons can be used in a practical implementation of the BB84 quantum key distribution protocol.
32 citations
TL;DR: In this paper, the separation of variables method for coordinate system, the extended boundary condition method, and the point-matching method that are used to solve the problem of light scattering by nonspherical particles are considered from a unified viewpoint.
Abstract: The separation of variables method for coordinate system, the extended boundary condition method, and the point-matching method that are used to solve the problem of light scattering by nonspherical particles are considered from a unified viewpoint. It is shown that, if the mathematical correctness condition (the Rayleigh hypothesis) holds, these methods are interrelated and are equivalent. The applicability ranges of the methods in the near- and far-field zones are analyzed, discussed, and compared on both analytical (based on analytical investigations) and practical (based on numerical calculations) grounds.
29 citations
TL;DR: In this paper, a comparative analysis of the Raman spectra of bulk PbS and pbS nanocrystals with average diameters of 6.6 and 3.8 nm has been performed.
Abstract: A comparative analysis of the Raman spectra of bulk PbS and PbS nanocrystals with average diameters of 6.6 and 3.8 nm has been performed. It is shown that the bands due to the LO phonons at the Γ point of the Brillouin zone dominate in the first- and second-order Raman spectra of the nanocrystals. Based on the analysis of the relative band intensities for the first- and second-order spectra a qualitative conclusion is drawn: the electron-LO-phonon interaction in PbS nanocrystals increases with a decrease in their size.
28 citations
TL;DR: In this paper, quantum-chemical calculations of the structure and electronic absorption spectra of the molecules D102, D149, and D205 of an indoline-thiazolidine series, which are used as sensitizers for solar cells, are performed.
Abstract: Based on the density functional theory, quantum-chemical calculations of the structure and electronic absorption spectra of the molecules D102, D149, and D205 of an indoline-thiazolidine series, which are used as sensitizers for solar cells, are performed. Circular dichroism spectra are predicted. The mechanisms by which intra- and intermolecular electron transfer occur upon excitation to a triplet state, as well as the relaxation mechanism, are described. The geometric and electronic structures of the molecules under study in the ground singlet and excited triplet states are considered, and the relation between their structure and photochemical properties is discussed.
21 citations
TL;DR: In this paper, the effect of defects on the structural periodicity of a one-dimensional photonic crystal has been investigated and a classification of single defects has been proposed, and it has been demonstrated that the position of defect minibands in the band gap of the spectrum of the crystal can be controlled by varying the type of defect and its location in the crystal structure.
Abstract: The effect exerted by defects that represent a local disturbance of the structural periodicity on the band spectrum of a one-dimensional photonic crystal has been investigated. A classification of single defects has been proposed. It has been demonstrated that the position of defect minibands in the band gap of the spectrum of the crystal can be controlled by varying the type of a defect and its location in the crystal structure. The presence of two defects in the structure leads to the formation of two minibands, so that the spacing between the minibands and their intensity depend on the type of defects and on the distance between them.
21 citations
TL;DR: In this paper, the authors investigated experiments of continuous-variable quantum information processing based on the teleportation scheme, which is realized by a twomode squeezed vacuum state and measurement-and-feedforward, is considered as an elementary quantum circuit as well as quantum communication.
Abstract: We investigate experiments of continuous-variable quantum information processing based on the teleportation scheme. Quantum teleportation, which is realized by a two-mode squeezed vacuum state and measurement-and-feedforward, is considered as an elementary quantum circuit as well as quantum communication. By modifying ancilla states or measurement-and-feedforwards, we can realize various quantum circuits which suffice for universal quantum computation. In order to realize the teleportation-based computation we improve the level of squeezing, and fidelity of teleportation. With a high-fidelity teleporter we demonstrate some advanced teleportation experiments, i.e., teleportation of a squeezed state and sequential teleportation of a coherent state. Moreover, as an example of the teleportation-based computation, we build a QND interaction gate which is a continuous-variable analog of a CNOT gate. A QND interaction gate is constructed only with ancillary squeezed vacuum states and measurement-and-feedforwards. We also create continuous-variable four mode cluster type entanglement for further application, namely, one-way quantum computation.
20 citations
TL;DR: In this paper, the results of the study of processes of electromagnetically induced transparency (EIT) and two-photon absorption (TPA) were presented for the ladder Ξ-system obtained using the 5S-5P-nD, mS system of levels of the 85Rb and 87Rb atoms with n = 5, 26, and 27 and m = 39 and 48.
Abstract: Experimental results of the study of processes of electromagnetically induced transparency (EIT) and two-photon absorption (TPA) are presented for the ladder Ξ-system obtained using the 5S-5P-nD, mS system of levels of the 85Rb and 87Rb atoms with n = 5, 26, and 27 and m = 39 and 48. To perform these studies, a high-temperature optical cell was designed with several regions with the following thicknesses L: 2 mm, 0.7 mm, and the region of 2–6 μm. The advantages of using thin cells over ordinary cells several centimeters thick are demonstrated. It is shown that the EIT resonance parameters for n = 5, 26, and 27 deteriorate insignificantly for thickness down to 700 μm. The TPA is recorded with the cell thickness decreasing down to L = 6 μm. It is shown that using the EIT and TPA processes makes it possible to measure the hyperfine and fine structures of highlying atomic levels. The influence of the cell walls is appreciable in recording the EIT resonances in the system 5S-5P-39S with L = 0.7 mm and in the system 5S-5P-48S with L = 2 mm. Possible applications of the processes studied are indicated.
TL;DR: In this paper, the Coulomb repulsion between electrons of the same site possessing opposite spin projections is considered and the derived effective equation has the form of a classical 2D sine-Gordon equation.
Abstract: The Maxwell equations for an electromagnetic field propagating in graphene are considered taking into account strong Coulomb repulsion between electrons of the same site possessing opposite spin projections. The derived effective equation has the form of a classical 2D sine-Gordon equation. Electrons are treated in terms of quantum formalism with allowance for the dispersion law in the presence of Coulomb interaction. The effective equation is analyzed numerically and the effect of Coulomb repulsion is revealed. It is shown that the system in an external homogeneous electromagnetic field, with its period much shorter than the characteristic pulse length, may show the amplification of an ultimately short pulse.
TL;DR: In this paper, the photoluminescence spectra of organic light-emitting diodes (OLEDs) with the ITO/α-NPD/ZnL/Ca:Al structure are studied.
Abstract: It is studied how the introduction of various substituents into the composition of organic ligands affects the photoluminescence spectra of new zinc(II) complexes with tetradentate Schiff bases H2L (derivatives of salicylic aldehyde (H2SAL1, H2SAL2) and o-vanillin (H2MO1, H2MO2) with ethylenediamine and o-phenylenediamine) in the form of bulk solids and thin films. It is demonstrated that the emission spectra of bulk solid complexes without o-phenylenediamine bridges (ZnSAL1 and ZnMO1) contain additional long-wavelength bands compared to the spectra of corresponding thin films. In the case of films obtained from [ZnSAL1]2 dimer complexes, the long-wavelength band is dominant. At the same time, the photoluminescence spectra of ZnSAL2 and ZnMO2 complexes with o-phenylenediamine bridges are similar in the case of solid samples and thin films. The electroluminescent properties of organic light-emitting diodes (OLEDs) with the ITO/α-NPD/ZnL/Ca:Al structure are studied. The bathochromic shift of the electroluminescence peaks of OLEDs with respect to the photoluminescence spectra of bulk solid samples and thin films is probably related to the formation of exciplexes at the α-NPD/ZnL interface. The electroluminescence spectra of OLEDs based on [ZnSAL1]2 show a hypsochromic shift of the emission maximum, which can be caused by a shift of the recombination region into the α-NPD layer.
TL;DR: In this paper, a PL model of a planar multiply scattering multilayer plant tissue is developed based on the expansion of radiation intensity in spherical harmonics, and the dependences of differential backscattering and fluorescence coefficients on the chlorophyll concentration are numerically studied in the first-order PL approximation.
Abstract: A PL model of a planar multiply scattering multilayer plant tissue is developed based on the expansion of radiation intensity in spherical harmonics. The dependences of differential backscattering and fluorescence coefficients on the chlorophyll concentration are numerically studied in the first-order PL approximation. It is shown that the PL approximation yields the results that are close to the numerical Monte Carlo solution (the deviations do not exceed 5.3%). The contribution of fluorescence to the backscattering intensity is calculated to reach 16% at high chlorophyll concentrations.
TL;DR: In this article, the optical pump-probe method, which makes it possible to determine the energy relaxation rate for excited electron-hole pairs and excitons in semiconductor quantum dots (QDs), is theoretically described.
Abstract: The optical pump-probe method, which makes it possible to determine the energy relaxation rate for excited electron-hole pairs and excitons in semiconductor quantum dots (QDs), is theoretically described. A scheme in which the carrier frequencies of optical pump and probe pulses are close to resonance with the same interband transition in the QD electron subsystem (degenerate case) is considered. The pump-induced probe energy absorption is analyzed as a function of the delay time between the pump and probe pulses. It is shown that under certain conditions this dependence is reduced to monoexponential, whose exponent is proportional to the energy relaxation rate for the considered state of electron-hole pairs and excitons. The size dependence of the energy relaxation rate of the electron-hole pair states is modeled by the example of PbSe-based QDs, whose electron subsystem is in the strong-confinement regime.
TL;DR: In this article, the authors considered the possibility of the giant enhancement of hyper-Raman scattering by molecules adsorbed on rough metal surfaces and proposed a theory based on the qualitative consideration of electromagnetic field enhancement near some model rough surfaces and individual irregularities, as well as on the quantum-mechanical features of dipole and quadrupole interactions of light with molecules.
Abstract: The possibility of the giant enhancement of hyper-Raman scattering by molecules adsorbed on rough metal surfaces is demonstrated. The theory is based on the qualitative consideration of electromagnetic field enhancement near some model rough surfaces and individual irregularities, as well as on the quantum-mechanical features of dipole and quadrupole interactions of light with molecules (as in the theory of surface-enhanced Raman scattering), proposed by the author. A consideration of symmetric molecules makes it possible to obtain selection rules for surface-enhanced hyper-Raman scattering (SEHRS) spectra and establish such a regularity as the occurrence of strong forbidden lines (which are due to totally symmetric vibrations); these lines are transformed according to unitary irreducible representation in molecules with the symmetry groups C
nh
, D, and higher. An analysis of the data in the literature for trans-1,2-bis (4-pyridyl)ethylene and pyridine molecules shows that their spectra can be explained in terms of the dipole-quadrupole theory of SEHRS. At the same time, the analysis of the SEHRS spectra of pyrazine revealed the presence of strong forbidden bands due to totally symmetric vibrations. This finding substantiated the proposed theory, which makes it possible to interpret the entire spectrum in detail. These results are in good agreement with the general mechanism of the optical effects enhanced by molecules adsorbed on metal surfaces, which was developed by the author.
TL;DR: In this paper, a method for collating two circular scales, one of which is determined by the prism upon its rotation on a rotary table, while the other is the device's own scale.
Abstract: To determine the precise values of angles stored and reproduced by a new multivalued measure of plane angles, i.e., a holographic prism, it is expedient to use a procedure for collating two circular scales, one of which is determined by the prism upon its rotation on a rotary table, while the other is the device’s own scale. The two scales are considered to be equivalent. The collation procedure is discussed taking into account target (deviations of sought values of angles of both scales from their nominal values) and a number of nuisance parameters of the procedure. The scheme of the collation device is considered. The geometric model that determines sources of errors caused by design features of signal reading and recording devices of the holographic prism is analyzed.
TL;DR: The spin Hamiltonian method in combination with ab initio calculations of the spin characteristics of quantum registers that include an electron spin S = 1 of a single NV center in the ground electronic state and nuclear spins I = 1/2 of several atoms 13C located at different lattice sites near the vacancy of the NV center is applied to find eigenvalues and eigenfunctions of spin systems as discussed by the authors.
Abstract: The spin Hamiltonian method in combination with ab initio calculations of the spin characteristics of quantum registers that include an electron spin S = 1 of a single NV center in the ground electronic state and nuclear spins I = 1/2 of several atoms 13C located at different lattice sites near the vacancy of the NV center is applied to find eigenvalues and eigenfunctions of spin systems NV + n
13C for cases where the lattice sites nearest to the vacancy of the NV center contain one, two, or three 13C nuclear spins, as well as for cases where 13C atoms are located at sites more distant from the vacancy. For these single spin NV + n
13C systems, the spectra of optically detected magnetic resonance (ODMR) are calculated, which agree well with available experimental data.
TL;DR: In this paper, the spin Hamiltonian method was used to find the hyperfine interaction tensors for a quantum register that includes an electron spin S = 1 of a single NV center in the ground electronic state and nuclear spins I = 1/2 of several isotopic atoms 13C located at different lattice sites near the vacancy of the NV center.
Abstract: Details of the application of the spin Hamiltonian method for studying spin characteristics of a quantum register that includes an electron spin S = 1 of a single NV center in the ground electronic state and nuclear spins I = 1/2 of several isotopic atoms 13C located at different lattice sites near the vacancy of the NV center. Two methods of finding the hyperfine interaction tensors for these NV + n13C spin systems are considered, one of which is based on the conventional electron spin resonance (ESR) method, while the other involves methods of quantum chemistry. The results of the latter method are compared with ESR data and with spectra of optically detected magnetic resonance (ODMR) and with the character of the modulation of the ODMR echo decay observed in single NV + n13C systems. This comparison shows that the ab initio modeling of the spin characteristics of diamond nanoclusters containing NV centers makes it possible to obtain quantitative spin characteristics of the quantum registers under study.
TL;DR: In this article, the interaction between negatively charged CdTe quantum dots and tetrasulfophthalocy-anine (TSPC) molecules in weak acid and alkaline media was investigated by spectral-luminescence methods.
Abstract: The interaction between negatively charged CdTe quantum dots (QDs) and tetrasulfophthalocy-anine (TSPC) molecules in weak-acid and alkaline media has been investigated by spectral-luminescence methods. Similarly charged QDs and TSPC molecules are found to form complexes that exhibit energy transfer from QDs to TSPC according to the mechanism of fluorescent resonance energy transfer. The channels of QD-luminescence quenching that compete with the intracomplex energy transfer and their contribution to the total QD-luminescence quenching are discussed. A model of the formation of complexes between similarly charged QDs and molecules is proposed.
TL;DR: In this article, the effect of significant narrowing of the fluorescence spectrum from a nanocell that contains a column of atomic Rb vapor with a thickness of L = 0.5λ was experimentally demonstrated.
Abstract: It has been experimentally demonstrated that the use of the effect of significant narrowing of the fluorescence spectrum from a nanocell that contains a column of atomic Rb vapor with a thickness of L = 0.5λ (where λ = 794 nm is the wavelength of laser radiation, whose frequency is resonant with the atomic transition of the D1 line of Rb) and the application of narrowband diode lasers allow the spectral separation and investigation of changes in probabilities of optical atomic transitions between levels of the hyperfine structure of the D1 line of 87Rb and 85Rb atoms in external magnetic fields of 10–2500 Gs (for example, for one of transitions, the probability increases ∼17 times). Small column thicknesses (∼390 nm) allow the application of permanent magnets, which facilitates significantly the creation of strong magnetic fields. Experimental results are in a good agreement with the theoretical values. The advantages of this method over other existing methods are noted. The results obtained show that a magnetometer with a local spatial resolution of ∼390 nm can be created based on a nanocell with the column thickness L = 0.5λ. This result is important for mapping strongly inhomogeneous magnetic fields.
TL;DR: In this article, shape distortions of magneto-optical resonances in emission of an extended source are considered, and a simple procedure of taking into account distortions and of determining positions of resonances on the magnetic field scale and their widths is proposed.
Abstract: Shape distortions of magneto-optical resonances in emission of an extended source are considered. The shape deformation of the magneto-optical structures is shown to be created by a longitudinal spatial inhomogeneity of the magnetic field. A simple procedure of taking into account distortions and of determining positions of resonances on the magnetic field scale and their widths is proposed.
TL;DR: In this paper, the formation kinetics of silver nanoparticles in photo-thermo-refractive glasses during heat treatment after ultraviolet and fast-electron irradiation were investigated.
Abstract: We present experimental results on the formation of silver nanocrystals in photo-thermo-refractive glasses during heat treatment after ultraviolet and fast-electron irradiation. We compare the optical density spectrum of samples at different stages of heat treatment. We show that the difference in the formation kinetics of silver nanoparticles is determined by the spatial redistribution of silver ions during electron irradiation and the change in the chemical composition of near-surface layers of glass.
TL;DR: In this paper, a method for reconstructing the radial dependence of the structural characteristic of the refractive index of air in an axisymmetric supersonic gas flow from the variance of intensity fluctuations of a laser beam that is transmitted through the flow at different distances from the jet symmetry axis is proposed.
Abstract: A method for reconstructing the radial dependence of the structural characteristic of the refractive index of air in an axisymmetric supersonic gas flow from the variance of intensity fluctuations of a laser beam that is transmitted through the flow at different distances from the jet symmetry axis is proposed. An expression that relates the relative intensity variance on the beam axis as a function of the aiming distance and the radial dependence of the structural characteristic is obtained. To invert this expression, the Abelian transformation is used. The parameters of the jet module of an AT-326 wind tunnel at the Institute of Theoretical and Applied Mechanics of the Siberian Branch of the Russian Academy of Sciences are modeled.
TL;DR: In this paper, the magnetic resonance frequency shifts caused by spin exchange collisions between 87Rb and 133C atoms were calculated and temperature dependences of magnetic resonance frequencies were drawn for two hyperfine states (F = 1, 2) of 87R b atoms.
Abstract: Magnetic resonance frequency shifts caused by spin-exchange collisions between 87Rb and 133Cs atoms are calculated, and temperature dependences of magnetic resonance frequency shifts are drawn for two hyperfine states (F = 1, 2) of 87Rb atoms. The obtained dependences are compared with experimental data.
TL;DR: Complex cross sections of the spin exchange were calculated for interacting Na and K atoms based on the data on the singlet (X 1Σ+) and triplet (a 3 Σ+) potentials that describe the interaction of these alkali-metal atoms in the ground state as mentioned in this paper.
Abstract: Complex cross sections of the spin exchange are calculated for the first time for interacting Na and K atoms based on the data on the singlet (X1Σ+) and triplet (a3Σ+) potentials that describe the interaction of these alkali-metal atoms in the ground state. The obtained cross sections allow one to theoretically consider the polarization transfer processes and calculate the relaxation times and the magnetic resonance frequency shifts caused by Na-K spin-exchange collisions.
TL;DR: In this article, the anharmonic frequencies of fundamental vibrations, overtones, and combination vibrations, as well as the intensities of absorption bands in the IR spectrum of uracil, are calculated.
Abstract: The anharmonic frequencies of fundamental vibrations, overtones, and combination vibrations, as well as the intensities of absorption bands in the IR spectrum of uracil, are calculated. The anharmonic quartic force field and the third-order dipole moment surface calculated by the DFT quantum-mechanical method (B3LYP/6-31+G(d,p)) are taken as the initial parameters. The anharmonic frequencies and intensities of vibrations are determined using the second-order perturbation theory in the form of contact transformations. Multiple Fermi resonances and polyads are determined by the diagonalization of a small interaction matrix of vibrations of different types (fundamental, combination, and overtone frequencies). The total experimental IR spectrum of matrix-isolated uracil is interpreted. It is shown that the used method of calculating anharmonic frequencies and intensities can form a basis for anharmonic calculations of vibrations of moderate molecules.
TL;DR: In this article, a new algorithm for controlling the flexible mirror by the signal of the volume atmospheric scattering is proposed and its efficiency is studied, and it is shown that the developed algorithm makes it possible to considerably reduce the compensation time of distortions compared to the gradient method.
Abstract: The possibility of compensating distortions of the initial wavefront of a partially coherent beam by the backscattered radiation power is analyzed. A new algorithm for controlling the flexible mirror by the signal of the volume atmospheric scattering is proposed and its efficiency is studied. It is shown that the developed algorithm makes it possible to considerably reduce the compensation time of distortions compared to the gradient method.
TL;DR: In this paper, a simple and efficient method is proposed for obtaining a thin layer of transformer oil in a standard cell for the recording of UV spectra, which is shown to be promising for the monitoring and qualitative analysis of the composition and content of aromatic compounds in transformer oils during the operation of power transformers.
Abstract: A simple and efficient method is proposed for obtaining a thin layer of transformer oil in a standard cell for the recording of UV spectra. UV and visible absorption spectra of fresh, used, and aged (under model conditions) transformer oil of the GK type have been recorded, interpreted, and compared. The method is shown to be promising for the monitoring and qualitative analysis of the composition and content of aromatic compounds in transformer oils during the operation of power transformers.
TL;DR: In this paper, the concentrations of products of liquid and gaseous water decomposition under the action of VUV (7n = 172 nm) radiation are calculated, and it is shown that the VUV radiation causes efficient formation of highly reactive *OH radicals.
Abstract: The concentrations of products of liquid and gaseous water decomposition under the action of VUV (7n = 172 nm) radiation are calculated. It is shown that the VUV radiation causes efficient formation of highly reactive *OH radicals. The application the products of water photodecomposition is exemplified by the possibility of degradation of polychlorinated biphenyl upon interaction with these products.