An investigation of radiative transition probabilities for the A1Σu+-X1Σg+ bands of Na2

The absolute radiative transition probabilities are calculated for previously observed spontaneous emission from A¹Σ_u⁺ (v′,J′) → X¹Σ_g⁺ (v″, J″ = J′ ± 1) reported in the preceding paper and by Woerdman (Chem. Phys. Lett.53, 219 (1978)). The calculations employ accurate hybrid potential energy curves, based on Rydberg-Klein-Rees (RKR), ab initio and long-range results, and a hybrid transition moment function, based on ab initio calculations. These calculated probabilities are compared with the various experimental results; while overall agreement is reasonable, detailed differences do occur.     

Two-body effects on baryon magnetic moments and radiative decays of mesons

We demonstrate that the two-body interaction effects involving spectator quark can account for the discrepancy between theory and experiment for the baryon magnetic moments and meson radiative decays.     

A q-integral representation of Rogers' q-ultraspherical polynomials and some applications

Aq-integral representation of Rogers'q-ultraspherical polynomialsC _n (x;β∥q) is obtained by using Sears' summation formula for balanced non-terminating₃ φ ₂ series. It is then used to give a simple derivation of the Gasper-Rahman formula for the Poisson kernel ofC _n (x;β∥q). As another application it is shown how this representation can be directly used to give an asymptotic expansion of theq-ultraspherical polynomials.     

Non-aqueous redox titrations with iodine and iodine halides. Determination of xanthates and dithiocarbamates

Summary Iodine and iodine halides (monobromide, monochloride and trichloride) solutions in acetonitrile have been used as oxidimetric reagents for the visual and potentiometric determination of alkali metal salts of xanthic and dithiocarbamic acids also dissolved in acetonitrile. The methods are simple, accurate, rapid and widely applicable.

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Zusammenfassung Jod und dessen Halogenverbindungen (Monobromid, Monochlorid und Trichlorid) in Acetonitril gelöst wurden als oxydimetrische Reagenzien zur visuellen und potentiometrischen Titration von Alkali-Xanthogenaten und-dithiocarbamidaten in dem genannten Lösungsmittel verwendet. Das Verfahren ist einfach, genau und vielseitig anwendbar.

     

Evaluation of the photoelastic constants of ionic crystals

A theoretical model, for evaluating the photoelastic constants of ionic crystals, has been developed by considering the short range repulsive interactions between nearest and next nearest neighbours, the van der Waals potentials and three body interactions as well as taking into account the electronic polarizabilities of cations and anions. The model has been applied to calculate the photoelastic constants of RbC1, RbBr and RbI crystals. The results obtained in the present study are in good agreement with experimental data.     

Dielectric properties of alkali halide and alkaline earth oxide crystals

The deviations of ionic charge and compressibility from their nominal values in alkali halides and alkaline earth oxide crystals have been discussed and explained in terms of a theory based on shell model and exchange charge interactions originally developed by Dick and Overhauser. The exchange charge polarization parameters have been evaluated in the present study using the appropriate values of overlap integrals. It has been concluded that the second neighbour short range forces have significnant magnitudes in alkaline earth oxides.     

Electromagnetic mass splittings of heavier hadrons in quantum chromodynamics

The electromagnetic mass splittings of heavier hadrons are estimated in the framework of gauge theory model where ligher quarks are taken to behave relativistically and the spatial wave functions are described by the spin-spin interaction affected relative distances between quarks. The predictions for (Ξ⁻-Ξ⁰), (Σ*⁰−Σ*⁺), (Ξ^*−-Ξ^*0), (D _c ⁺−D _c ⁰) and (D _c ^*+ −D _c ^*0 ) are in fair agreement with the experimental data available whereas those for (D _b ⁻ −D _b ⁰ ) and (D _b ^*− −D _b ^*0 ) are in qualitative agreement with other theoretical estimates.     

Second upper-bound on the three-phonon resistivity in Ge

Contributions of different allowed three-phonon resistances in Ge have been presented in the second upper-bound W^>₁. It is found that the deviation of W^>₁ from W^>₀, the first upper-bound, is markable. As a matter of fact W^>₁ is shown to be less than W^>₀ by about 14% at 100°K and about 5% at 300°K.