Structural dynamic models and anharmonic analysis of vibrational states of polychloro-substituted dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxin

We have analyzed the vibrational spectra of β-tetrachloro-substituted and ortho-chlorosubstituted dibenzo-p-dioxin using the DFT/B3LYP/6-31G(d) method, in the anharmonic approximation. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 21–24, January–February, 2007.     

Anharmonic Analysis of the Vibrational States of Phenyldichlorarsine and Phenyldichlorphosphine

Using the DFT/B3LYP method with the basis set 6-31G*(**), we analyzed the vibrational spectra of the conformers phenyldichlorarsine and phenyldichlorphosphine in the anharmonic approximation. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 4, pp. 557–559, July–August, 2005.     

Analysis of vibrational spectra of methyl-substituted uracils in the anharmonic approximation

We have analyzed the vibrational spectra of uracil and its methyl-substituted derivatives using the DFT/B3LYP/6-31G(p,d) method, in the anharmonic approximation. We have shown that it is possible to use second-order anharmonic theory of vibrational spectra in predictive calculations for substituted uracils. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 431–436, July–August, 2006.     

Quantum chemical calculation of normal molecular vibrations for substituted five-member chalcogen heterocyclic compounds taking anharmonicity into account

The DFT/B3LYP/6-31G* method is used in an anharmonic approximation to analyze the vibrational spectra of substituted furan, thiophene, and selenophene (3,4- and 2,5-dimethyl-, dichloro-, and diaza-; and 2,3,4,5-tetrachloro-). The influence of resonance effects is clarified. in final form, December 16, 2008. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 2, pp. 170–175, March–April 2009.     

Vibrational spectra and structural dynamic models of halosubstituted formaldehyde

The DFT/B3LYP method with 6-31G*(**) basis sets has been used to analyze the vibrational spectra of halo-substituted formaldehyde in the anharmonic approximation. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 683–686, September–October, 2006.     

Vibrational spectra of benzophenone conformers

We have used direct quantum DFT methods to calculate the parameters of the adiabatic potential of four benzophenone conformers. According to the data obtained, the existence of only one conformer is possible (C₁ symmetry) for the free benzophenone molecule, for which torsional vibrations of the benzene moieties are reproduced and for which we calculated the vibrational spectrum in the anharmonic approximation of the theory of molecular vibrations. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 5, pp. 561–564, September–October, 2007.     

Absorption,fluorescence, and SERS spectra of sanguinarine at different pH values

We have studied the absorption, fluorescence, and surface-enhanced Raman scattering (SERS) spectra of sanguinarine using a silver hydrosol and an electrochemical cell with a silver working electrode for different pH values in the medium. We carried out quantum chemical calculations in order to interpret the electronic and vibrational spectra and to establish their correlations with the structure of the molecules. We optimized the structure and determined the spectral characteristics of the cationic and neutral forms of the sanguinarine molecules in solution and adsorbed on the surface of an anodized Ag electrode for different potentials. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 5, pp. 604–609, September–October, 2007.     

IR absorption and surface-enhanced Raman spectra of the isoquinoline alkaloid berberine

We present the IR absorption and surface-enhanced Raman scattering (SERS) spectra of the isoquinoline alkaloid berberine adsorbed on a silver hydrosol and on the surface of a silver electrode for different potentials. Based on quantum chemical calculations, for the first time we have assigned the vibrations in the berberine molecule according to vibrational mode. The effect of the potential of the silver electrode on the geometry of sorption of the molecule on the surface is considered, assuming a short-range mechanism for enhancement of Raman scattering. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 31–36, January–February, 2007.     

Search for and elimination of dependences between vibrational coordinates in modeling spectra of large molecules

We have investigated an algorithm allowing us to reliably identify an arbitrary number of complex linear dependences between vibrational coordinates in a molecular model of very high dimensionality. These dependences are eliminated in the step for diagonalization of the kinetic part of the vibrational Hamiltonian. We have carried out computer experiments allowing us to propose optimal rules for designing appropriate computer programs for working with a vibrational Hamiltonian of very high dimensionality. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 561–565, September–October, 2006.     

Calculation of frequencies of normal vibrations and interpretation of IR spectra for 2,3-dihydro-3-O-(1,4-naphthoquinon-2-yl)-2-oxo-1,4-naphthoquinone derivatives

We have used B3LYP/6-31(d) density functional theory to calculate the frequencies and modes of the normal vibrations of 2-oxo-2,3-dihydro-and 2-methoxy-1,4-naphthoquinones. Based on these calculations within an additive model, we have assigned the carbonyl bands in the IR spectra of 2,3-dihydro-3-O-(1,4-naphthoquinon-2-yl)-2-oxo-1,4-naphthoquinones (diquinones 1–4). We have carried out a direct calculation of the vibrational spectra for diquinones 1–4 using PBE and B3LYP correlation functionals. We have shown that the calculation of the vibrational spectra of the diquinones based on an additive model on the whole is quite consistent with the results of direct calculations and the experimental spectra. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 713–720, November–December, 2006.     

Calculation and analysis of vibrational spectra of adenine–thymine,guanine–cytosine,and adenine–uracil complementary pairs in the condensed state

We have calculated the frequencies of the normal vibrations of the complementary nucleic acid base pairs adenine–thymine, guanine–cytosine, adenine–uracil, corresponding to the Watson–Crick structure, and the adenine–uracil pair, corresponding to the Hoogsteen structure, in condensed states and we interpret the spectra. We determine the contributions of hydrogen bonds to the vibrational modes of the complementary pairs. We have analyzed the nature of the relative displacements of the nucleic acid bases as integral molecular units along the hydrogen bonds. We show the role of hydrogen bonds in tautomeric interconversions of complementary nucleic acid base pairs. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 1, pp. 84–92, January–February, 2009.     

Theoretical analysis of vibrational spectra of tautomeric purine forms

A theoretical analysis of vibrational spectra of purine tautomers was carried out using the DFT/B3LYP/6-31G(d)* method. The influence of intermolecular interaction in purine dimers was estimated. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 23–27, January–February, 2008.     

Structural Dynamic Models and Vibrational Spectra of Nitrobenzene and Nitropyridines

Using the DFT/B3LYP method with the basis sets 6-31G*(**), we analyzed the vibrational spectra of nitrobenzene and nitropyridines for free molecules and their solutions in water, ethanol, and benzene. The influence of a solvent on the behavior of the characteristic spectral parameters of nitrobenzene is revealed, and the assignment of vibrations for nitropyridines is given. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 4, pp. 450–453, July–August, 2005.     

The vibrational spectra and structural properties of Me7Eu2UO2(PO4)5 crystals

We investigate the vibrational spectra of crystals of ternary orthophosphates Me₇Eu₂UO₂·(PO₄)₅ (Me–Na, Rb, Cs) obtained by solid-phase synthesis. We show that in these materials the effect of coordination distorts the geometry of the PO ₄ ³⁻ tetrahedron and decreases its symmetry. We conclude that the PO ₄ ³⁻ tetrahedrons in Me₇Eu₂UO₂(PO₄)₅ occupy two nonequivalent positions in the lattice. The character of manifestation and the number of oscillation frequencies observed allow the assumption that they have the C_3v- and C₂-symmetry. This symmetry of two crystallographically nonequivalent groups of PO ₄ ³⁻ ensures a complete set of bands in the IR absorption spectra of the crystals investigated. We show that these crystals exhibit chain structural motifs. Translated from Zhurnal Prikladnoi Spektroskopii, Vol, 64, No. 4, pp. 467–470, July–August, 1997.     

High-resolution spectrum of the first triad of D<Subscript>2</Subscript><Superscript>32</Superscript>S interacting states

The high-resolution spectrum of the D₂S molecule registered with a Bruker IFS 120HR Fourier spectrometer in the range 2000–4200 cm^–1 is analyzed. The spectroscopic parameters of the (110), (011), and (030) vibrational states are obtained. They reproduce rotational energy levels with the accuracy close to experimental one (a total of 737 rovibrational energies is considered corresponding to 2590 transitions up to J ^max = 21). Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 3–7, February, 2009.     

Vibrational spectra of activated rei of wolframile-phosphate glasses

The vibrational spectra of wolframile-phosphate glasses with a high concentration of WO ₂ ²⁺ and Ln³⁺ ions were investigated and the structure of these glasses was analized. It is shown that the investigated glasses are formed predominantly by chain polyphosphates. Tungstate enters into the net of the glass in octahedral coordination, “stitching” the polyphosphate chains together but not isomorphously substituting phosphorus. In the glass structure nonlinear wolframile groups with the multiple tungsten-oxygen bonds are formed. The introduction of lanthanide oxides into the glass composition causes the average degree of its polymerization to decrease. F. Skorina Gomel' State University, 104 Sovetskaya St., Gomel', 246699, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 2, pp. 236–241, March–April, 1997.     

Vibrational spectra of a plasma-polymerized coating on the surface of a silicon single crystal

The composition and structure of plasma-polymerized coatings on the surface of a silicon single crystal are studied using methods of mass spectrometry and vibrational spectroscopy. It is established that the coating on the side of the surface is a set of ordered and unordered regions of branched chains of halogenocarbons and halogenohydrocarbons. A significant thickness of the coating-substrate transition layer contains silicon carbide and nitrogen dissolved in carbon. A great bulk of the coating is made up of amorphous carbon. The coating mass contains adsorbed gases that block reactive centers. Consideration is given to the special features of recording of vibrational spectra, the coating structure, its differences over the depth, the structural difference between the coating and a polymer film, and aging of the polymer material. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 338–344, May–June, 1999.     

Influence of size effects on <Emphasis Type="Italic">para</Emphasis>-dichlorobenzene lattice dynamics

We have obtained experimental low-frequency Raman spectra for light scattering by nanoparticles of para-dichlorobenzene of size ∼300–70 nm. As their sizes decrease, the line frequencies decrease. The size of the nanoparticles was determined using an electron microscope. We found that in the lattice vibrational spectrum of nanoparticles of size 300–70 nm, a summed spectrum appears from α-para-dichlorobenzene and β-para-ichlorobenzene. This is consistent with molecular dynamics calculations of the structure of the nanoparticle and calculations of the histograms for the lattice vibrational spectra by the Dean method.     

Raman study of oxidation-reduction dispersion of silver

We have examined the process of redox dispersion of silver, using a solution simultaneously containing an oxidizing agent (potassium ferricyanide) and a reducing agent (sodium borohydride). We have studied the changes over time in the Raman spectra of the indicated solution when no silver particles are present and when such particles are added to the solution. We have established that the silver particles have a catalytic effect on the reaction between potassium ferricyanide and sodium borohydride, kinetically slowed down in alkaline medium. The original silver particles (1–20 μm) undergo redox dispersion as a result, and Ag particles are formed with sizes 1–10 nm. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 182–186, March–April, 2006.     

Quantum-chemical calculations of the structure,vibrational spectra,and torsional and inversion potentials of methylcarbamate

We present results of ab initio and DFT calculations of the structure, potential functions of the methyl group internal rotation and the amino group inversion, and vibrational frequencies and intensities in IR and Raman spectra of methylcarbamate. The calculations were carried out using different basis sets in the HF, MP2, and DFT/B3LYP approximations. The influence of both the basis set size and the allowance for electronic correlation on peculiarities of the structure of the amino group in methylcarbamate has been analyzed. It is shown that the B3LYP/6-311++G(2d, p) and B3LYP/cc-pVDZ calculations reproduce highly accurately experimental geometric parameters of methylcarbamate. Parameters of torsional and inversion potentials and characteristics of vibrational spectra calculated in different approximations show satisfactory agreement with experimental values. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 349–357, May–June, 2009.