Atomic static multipole polarizabilities

Rivail and Rinaldi's scheme to work out the quantum static multipole polarizabilities have been extended to recover convergence in it. Our expressions give exact static multipole polarizabilities for the atomic hydrogen and give reasonable values for He-sequence.     

Spiky whistler solitons

Purely ponderomotive force-driven electron motion is shown to produce spiky electron whistler solitary waves.     

Microdetermination of oxprenolol hydrochloride and metoprolol tartrate with ammonium metavanadate

A micro method has been developed for the determination of oxprenolol hydrochloride and metoprolol tartrate in pure form and in pharmaceutical preparations, with vanadium(V) in acidic medium.     

Magnetostatic mode in a sheared magnetic field

The effect of magnetic shear on the magnetostatic mode is considered. It is found that the lifetime of the mode is shortened, leading to a reduction of the corresponding cross-field diffusion.     

Nonlinear Excitation of Plasma Convection

Parametric excitations of electrostatic convective cells by drift waves as well as magnetostatic cells by Alfvén waves are considered. The growth rates are calculated for various limits of interest to plasma diffusion studies; our results agree with computer simulations. The problem of crossfield diffusion is also discussed. Finally, the coupling of magnetostatic modes with electrostatic modes is investigated and a variational principle for coalescence of magnetic islands is formulated.     

Theoretical evaluation of debye-waller factors for f.c.c. metals

Summary The temperature dependence of the Debye-Waller factor exponents for five f.c.c. metals—copper, silver, aluminum, nickel and gold—has been carried out under the modified axially symmetric model of Shukla and Closs. The theoretical computations are compared with the experimental one ofY θ_M and ≪u ²≫, namely the Debye-Waller factor temperature parameter, the effective X-ray characteristic temperature and the root mean square displacement. Reasonable agreement has been obtained between the theory and the experiment.

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Raassunto Si è calcolata la dipendenza dalla temperature degli esponenti del fattore di Debye e Waller per cinque metalli f.c.c.—rame, argento, alluminio, nickesl ed oro—secondo il modello modificato a simmetria assiale di Shukla e Closs. I calcoli teorici sono confrontati con i dati sperimentali suY,430-1 ed ≪u ²≫, cioè il parametro di temperature del fattore di Debye e Waller, la temperatura caratteristica efficace dei raggi X e lo spostamento della radice qudratica media. Si è ottenuto un ragionevole accordo tra teoria ed esperimenti.

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Реуме На основе модыфицированной аксиалтно симметричной модели Шукла и Клосса вЫчисляется темчературная зависимость фактора Дебая-Уоллера для пяти гранецентрированных металлов—меди, серебра, алюминия, нилеля и золота. Теогетичеслие вЫчисления сравниваются с зкспериментальнымн данными для У, θ_M и <u ²>, т.е. для температурного парамепра фактора Дебая-Уоллера, зффективной характеристической температуры и среднего квадрапа смешения. Получается, разумное согласие между теорией и зкспериментом.

     

Darstellung von Pentahalogenopyridinosmaten(IV) in unpolaren Lösungsmitteln

Preparation of Pentahalopyridineosmates(IV) in Nonpolar Solvents The reaction of hexahaloosmates(IV) with pyridine in nonpolar solvents gives pentahalopyridineosmates(IV) in good yield. Using this method [OsI₅py]^? is prepared for the first time. It could not be obtained by substitution reactions or photolysis of [OsI₆]^2? in pyridine. The new complex is characterized by electronic and vibrational spectroscopy.     

Quasiparticle approach to the modulational instability of drift waves coupling to zonal flows

The interaction between broadband drift mode turbulence and zonal flows has been studied through the wave-kinetic approach. Simulations have been conducted in which a particle-in-cell representation is used for the quasiparticles, while a fluid model is employed for the plasma. The interactions have been studied in a plasma edge configuration which has applications in both tokamak physics and magnetopause boundary layer studies. Simulation results show the development of a zonal flow through the modulational instability of the drift wave distribution, as well as the existence of solitary zonal flow structures about an ion gyroradius wide, drifting towards steeper relative density gradients.