http://dspace.nbuv.gov.ua:80/handle/123456789/115116 2026-04-24T12:42:17Z 2026-04-24T12:42:17Z Gordon, D.A. Volodina, V.A. Mikhailov, A.I. http://dspace.nbuv.gov.ua:80/handle/123456789/118476 2017-05-31T00:09:12Z 2013-01-01T00:00:00Z

Reactivity of free radical intermediates that form spontaneously during molecular chlorine action on acetylene and vinyl monomers at low temperatures Gordon, D.A.; Volodina, V.A.; Mikhailov, A.I. In this study ESR, UV, VIS and IR spectroscopy, chromatography, calorimetry, and elemental analysis were employed to show the spontaneous formation of free radicals under low-temperature action of molecular chlorine on acetylene monomer p-diethynylbenzene, and vinyl monomer acrylamide. These radicals are able to initiate chain reaction of polymerization of monomers at low temperatures. This reaction results in a completely soluble polymer with a yield of 25 %, while an insoluble cross-linked polymer has been obtained during polymerization of p-diethynylbenzene initiated by other means. For example, under radiolysis by 1000 kGy the soluble fraction of obtained polymer was ≈ 1% while the overall yield was ≈ 10%. p-Diethynylbenzene polymerizes at temperatures close to chlorine melting (170 K). Polymerization of acrylamide takes place in the temperature range of 180–210 K with an yield of polymer ≈ 10%. The low-temperature chlorination of a 20%-solution of acrylamide in glycerol enables a twofold increase of the polymer yield, and a tenfold decrease of the chlorine content in it.

2013-01-01T00:00:00Z Zholonko, N.N. http://dspace.nbuv.gov.ua:80/handle/123456789/118475 2017-05-31T00:03:16Z 2013-01-01T00:00:00Z

Diffusion model of the thermal conductivity plateau of weak solid solutions of neon in parahydrogen Zholonko, N.N. The diffusion kinetic of classic impurity particles has been investigated in the frame of one-dimensional two-level model and applied for the explanation of solid hydrogen thermal conductivity data with extremely low con-centrations of neon impurity in samples growth at different crystallization rates in which the plateau effect was observed. The main idea is that heavy isotopic impurities could segregate into thin long chains near dislocation cores if the growth rate is slow. Neon impurity chains can persist for a long time. Such rigid linear objects ensure inelastic scattering of phonons. The diffusion coefficient of neon atoms in (p-H₂)₁–cNec mixtures was estimated for the experimental conditions with с = 0.0001 аt. % and с = 0.0002 аt. %.

2013-01-01T00:00:00Z Gorbenko, Ie.Ie. Zhikharev, I.V. Troitskaya, E.P. Chabanenko, Val.V. Pilipenko, E.A. http://dspace.nbuv.gov.ua:80/handle/123456789/118474 2017-05-31T00:07:09Z 2013-01-01T00:00:00Z

Elastic properties of compressed cryocrystals in a deformed atom model Gorbenko, Ie.Ie.; Zhikharev, I.V.; Troitskaya, E.P.; Chabanenko, Val.V.; Pilipenko, E.A. A model with deformed atom shells is built to investigate the elastic properties of rare-gas crystals Ne and Kr under high pressure. It is shown that the observed deviation from the Cauchy relation cannot be adequately reproduced with taking into account of only the many-body interaction. The individual pressure dependence of is a result of competition of the many-body interaction and the quadrupole interaction associated with the quadrupoletype deformation of electron shells of the atoms during the displacements of the nuclei. Each kind of interaction makes a strongly pressure dependent contribution to . In the case of Ne and Kr, contributions of these interactions are compensated to the good precision, providing being almost constant against pressure.

2013-01-01T00:00:00Z Ivanov, A.Yu. Rubin, Yu.V. Egupov, S.A. Belous, L.F. Karachevtsev, V.A. http://dspace.nbuv.gov.ua:80/handle/123456789/118473 2017-05-31T00:08:47Z 2013-01-01T00:00:00Z

Fermi resonance in Ne, Ar and Kr-matrix infrared spectra of 5-bromouracil Ivanov, A.Yu.; Rubin, Yu.V.; Egupov, S.A.; Belous, L.F.; Karachevtsev, V.A. Low-temperature matrix isolation Fourier-transform infrared spectroscopy and quantum-chemical calcula-tions with DFT/B3LYP and MP2 methods were used for investigation of isolated 5-bromouracil (BrU) mole-cules. Only one tautomeric form of BrU was dominated in the low-temperature Ne, Ar, and Kr matrices. It was revealed that population of minor hydroxy-tautomers did not exceed 0.2%. Appearance of additional absorption bands in the region of stretching vibrations CO (about 1710 cm⁻¹) as well as of deformation ones (1297, 1093, 901 cm⁻¹) was explained by Fermi resonance. In Ne matrices the peak intensities of absorption bands assigned to the out-of-plane vibrations of the ring and exocyclic atoms were decreased sharply. For the first time, least square method with the using of polynomial was proposed for the corrective scaling of calculated frequencies of vibrations. It is shown that the correction of calculated frequencies with the polynomial of degree two permits to decrease the root-mean-square discrepancy between the calculated and experimental ones to 4–5 cm⁻¹ in the re-gion of 1500–500 cm⁻¹. The same polynomial may be applied for the correction of spectra of molecules with a similar structure.

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