Fluorescence anisotropy of acridinedione dyes in glycerol: Prolate model of ellipsoid

Time-dependent reorientations of resorcinol-based acridinidione (ADR) dyes in glycerol were studied using steady-state and time-resolved fluorescence studies. The difference between fluorescence anisotropy decays recorded at 460 nm when exciting at 250 nm and those obtained when exciting at 394 nm are reported. When exciting at 394 nm, the fluorescence anisotropy decay is bi-exponential, while on exciting at 250 nm a mono-exponential fluorescence anisotropy decay is observed. We interpret this in terms of different directions of the absorption dipole at 394 and 250 nm with the emission dipole respectively, which is experimentally validated and further analysed as a prolate model of ellipsoid.     

Spectroscopic investigation of 4f correlations in CeAg; comparison between LDA and many-body descriptions

High resolution photoemission and bremsstrahlung isochromat spectroscopy experiments have been carried out on CeAg and LaAg. From a comparison between these two compounds, we extract the cerium 4f spectral function, we compare it with band structure calculations and with many-body model simulations based on the single-impurity Anderson Hamiltonian. We show that the localized 4f charge estimated from previous band structure calculations cannot be identified with the 4f occupation number deduced from the Anderson model.     

The X-ray diffraction crystal structure determination and electron impact fragmentations of the gaseous ions of 3-(p-chlorophenyl)-1-methyltriazene-1-oxide and its 3-methyl derivative

The decomposition of the gaseous positive ions of the title compounds obtained by electron impact have been completely mapped. The X-ray structural determinations of these two substances established their identity definitively and allowed to reveal some interesting features of these molecules of pharmaceutical interest.     

Motion of a chain of bubbles in a vertical channel with a viscous fluid

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 87–91, May–June, 1991.     

Commutative semigroup cohomology

Triple cohomology for commutative semigroups is described in concrete terms and related to existing extensions.     

Analytic properties of solution of electronic Schrödinger equation

Moscow State University. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 88, No. 1, pp. 31–36, July, 1991.     

Spectral and voltammetric studies on titanium substituted Keggin-type heteropolyanions

Bonding and redox properties of mono- and dititanium substituted 12-heteropolytungsto-phosphates and their complexes with bivalent Mn, Co, Ni and Cu are studied by UV-Vis, ESR and cyclicvoltammetric techniques. The heteropoly blue analogue [Ti^IIITi^IVW₁₀PO₄₀]⁸⁻ is unstable and its presence in solution is proved by optical and ESR spectroscopy. ESR results reveal that the odd electron is trapped on the titanium atom at 77 K. The optical electronegativity of Ti(III) in this heteropoly blue is estimated to be 2.4 from the intervalence charge transfer (IVCT) bands. X-ray powder diffraction results show that the complexes K₅M^II[Ti₂W₁₀PO₄₀].xH₂O(M^II = Cu or Mn) are isomorphous with K₇[Ti₂W₁₀PO₄₀].6H₂O. Electronic spectroscopy indicates very high symmetry around the bivalent metal ion M in the K₅M^II[Ti₂W₁₀PO₄₀].xH₂O complexes. This high symmetry is confirmed in K₅Cu[Ti₂W₁₀PO₄₀] by the observation of dynamic Jahn-Teller (JT) distortion at 300 K and static JT distortion at 77 K.     

Bromination of 4-substituted thiazolylhydrazones

4-Phenyl- and 4-methylthiazolylhydrazones were brominated in chloroform and acetic acid. The use of 1.5 equivalents of bromine led to the exclusive formation of the 5-halo derivatives. Effects of substituents on the thiazole ring and of the hydrazone fragment aromatic ring on the course of the reaction were discovered.Urals State Technical University-UPI, 620002 Yekaterinburg. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 991–995, July, 1995. Original article submitted March 1, 1995.     

Pulsed gas lenses

The concept of a pulsed gas lens is proposed. Potential applications are envisaged and preliminary experiments with pulsed ray refraction are reported.     

FFT solution of the Robbins problem

An FFT method is described for the solution of Poisson's equationover a rectangular region with Robbins boundary conditions oneither one or two sides of the region, together with suitableconditions on the rest of the boundary. In contrast to earlierapplications of the FFT technique, the equations for the Fourierharmonic amplitudes do not decouple into simpler independentsystems and an effective iterative scheme is developed for thesolution of these equations. A theoretical convergence analysisis shown generally to support the results obtained from practicalcomputation. For the test problems considered the method isfound to take between 3 and 4 times the execution time for problemssoluble directly by the FFT technique.