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.     

The effect of complexing processes on energy transfer Tl+→Gd3+ and Tl+→Tb3+ in glass

T. Shevchenko Kiev University, 252022 Kiev, Pr. Akad. Glushakova, 6, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 3, pp. 192–196, May–June, 1995.     

Spectra and structure of energy levels of Pr3+ in crystals of yttrium and gadolinium oxyorthosilicates

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 6, pp. 123–129, November–December, 1995.     

Energy transfer as a method for investigation of the structure of electrolytes

S. I. Vavilov State Optical Institute, Russia, 199034, St. Peterburg, Birzhevaya Liniya, 12. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 3, pp. 38–42, May–June, 1995.     

Electron spectra of Me7Eu2UO2(PO4)5 crystals

Absorption and luminescence spectra of Me₇Eu₂UO₂(PO₄)₅ crystals (Me represents Na, Rb, or Cs) are investigated. It is established that the luminescence of Eu³⁺ ions in these crystals is sensitized by uranyl. The effect of the outer-sphere cation Me⁺ on the spectroscopic properties and structural features of the compounds under study is considered. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 89–94, January–February, 1999.     

Spectroscopy of Sm3+ activator centers in Ca3Ga2Ge4O14 single crystals

Results of investigations of spectroscopic properties of Ca₃Ga₂Ge₄O₁₄ single crystals activated with Sm³⁺ ions are reported. It is shown that Sm³⁺ ions in Ca₃Ga₂Ge₄O₁₄ form a type of activator quasicenter whose nature is associated with disordering of the matrix. I. Franko Lvov State University, 50, Dragomanov St., Lvov, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 296–298, March–April, 1998.     

Optical properties of pure and doped Y3Fe5O12 single crystals

Institute of Physics of Solids and Semiconductors, Academy of Sciences of Belarus, 17, P. Brovka Str., GSP, Minsk, 220072. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 63, No. 4, pp. 667–675, July–August, 1996.     

Spectral-luminescence and lasing properties of several morpholine derivatives of naphathalimide in different solvents

The spectral-luminescence properties, lasing ability, and time-resolved gain spectra of three morpholine derivatives of naphthalimide (substituted in position 4) in polar (ethanol and dimethylformanide) and nonpolar (diethyl ester and toluene) solvents are investigated. It is found that rotation of the morpholine group about the single bond connecting the group with the rest molecule takes place, which results in a shift of the gain spectrum towards the longwave region and decrease of the fluorescence quantum yield. Deceased. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 5, pp. 603–606, September–October, 1997.     

Raman spectroscopic study of the mineral guilleminite Ba(UO2)3(SeO3)2(OH)4·3H2O

The Raman spectrum of the mineral guilleminite Ba[(UO₂)₃O₂(SeO₃)₂](H₂O)₃ was studied and complemented by the infrared spectrum of this mineral. Both spectra were interpreted and compared with the spectra of marthozite, larisaite, haynesite and piretite, all of which should have the same phosphuranylite anion sheet topology. The presence of symmetrically distinct water molecules and hydrogen bonds was inferred from the spectra. This is in agreement with the crystal structural analysis of guilleminite. U O bond lengths in uranyl and O H···O hydrogen bond lengths were calculated from the Raman and/or infrared spectra of guilleminite. Copyright © 2008 John Wiley & Sons, Ltd.     

Vibrational spectra of Na4P2O7·10H2O

The IR and Raman spectra are measured and analysed for sodium pyrophosphate decahydrate. The spectra are interpreted on the basis of P₂O ₇ ⁴⁻ ion and water vibrations. The observed results fit with the features predicted for the factor goup model. The appearance of two sets of frequencies in the stretching and bending regions of water suggests the existence of two kinds of water molecules in the crystal. This is confirmed by deuterium substitution.     

Interchromophore interactions and energy transfer in covalently bound porphyrin-chlorine heterodimer

Energetis of interchromophore interactions in a covalently bound prophyrin-chlorine heterodimer (Por-O-Chl) is investigated at temperatures from 77 to 293 K in solvents with differing polarity (toluene, tetrahydrofurane, and diethyl ether: petroleum ester: isopropanole=5∶5∶2 mixture). We substantiate the conclusion that the strong quenching of fluoresence and phosphorescence of the porphyrin fragments in both stable isomers of the Por-O-Chl heterodimer is induced not by the photoinduced charge transfer but rather by efficient processes of singlet-singlet (probability F^SS=1.3·10¹¹ to 6.8°10¹⁰ sec⁻¹) and triplet-triplet (probability F^TT≥10⁸ sec⁻¹) radiationless electronic excitation transfer. It is shown that the S−S transfer takes place without quantum losses from the thermodynamically equilibrated S₁ state of the donor, and its dynamics and main regularities at temperatures from 77 to 293 K are described by the inductive resonance theory without any additional asssumptions. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 75–82, January–February, 1998.     

Density-functional study of CO adsorbed on RhN （N = 2-19） clusters

We investigate the structural, electronic and adsorption properties of one single CO molecule adsorbed on Rh_N (N = 2-19) clusters, using the density-functional theory in the spin-polarized generalized gradient approximation. It is found that the structural growth model of the Rh_N clusters transforms from double layers (N = 12-16) to three layers (N = 17-19). Three different adsorption types are the atop site adsorption for N = 6, 8, 9, 11, 12, the bridge site adsorption for N = 2-5, 7, 10, 13-15, 17 and the face adsorption for N = 16, 18, 19. The adsorption abilities of Rh_N clusters are related to C-O bond length, vibrational frequency, adsorption energy and the charge transfer between CO and Rh clusters as well as the electronic density of state. With the increase of Rh cluster size, the adsorption energy of CO adsorbed on Rh_N clusters tends to be 2.2 eV-2.3 eV, which is 0.2 eV-0.3 eV larger than the theoretical value (about 2.0 eV) of CO molecule adsorption on clean Rh (111) surface.