Intensity measurement of laser-excited fluorescence in the B3Πu(0+)-X1Σg+ system of diatomic lodine

Fluorescence was excited in the B³Π_u(0⁺)-X¹Σ_g⁺ system of diatomic iodine by means of the 5145-Å line of an Ar⁺ laser and the 6328-Å line of a HeNe laser. The resulting spectrum was recorded on a SPEX double monochromator and a quantitative measurement of the intensities was carried out. The variation of the electronic transition moment $\text{M(}\text{R}\text{)}$ with R centroid observed by us shows a behavior similar to what has been reported earlier.     

Determination of arsenic and zinc in tin oxide by X-ray fluorescence

Summary An XRF method to determine arsenic and zinc in high-purity tin oxide in the range of 10–1,000 ppm is described. The sample is pressed as a double-layer pellet and the analysis is carried out by using Philips PW-1220 X-ray spectrometer. Limits of detection are 13 ppm (As) and 8 ppm (Zn). Accuracy is better than 10% at a level of 50ppm; standard deviations are 8 and 9 % at this level.

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Bestimmung von Arsen und Zink in Zinnoxid mit Hilfe der Röntgenfluorescenz

Zusammenfassung Das beschriebene Verfahren eignet sich zur As- und Zn-Bestimmung im Bereich von 10 ppm–1000 ppm in Zinnoxid. Die Probe wird zu einer Doppelschichttablette gepreßt und die Analyse mit Hilfe eines Philips PW-1220 Röntgenspektrometers durchgeführt. Die Erfassungsgrenzen sind 13 ppm (As) bzw. 8 ppm (Zn). Die Genauigkeit ist besser als 10 % (50 ppm-Bereich); die Standardabweichung in diesem Bereich beträgt 8 bzw. 9 %.

     

Microstructure and topography of vapor deposited,sputtered and annealed (111) palladium films

The microstructural effects of argon ion bombardment and thermal annealing on vapor deposited (111) Pd films on mica substrates have been studied. Sputtering resulted in surface roughening as well as in the formation of an amorphous phase and double positioned twins. In the higher fluence zones, relatively large blisters were formed. Moderate annealing of the sputtered film did not restore the original smoothness of the surface. The hillocks became larger while their density decreased.     

Polymerization of styrene with VCl4–aluminum alkyls

Polymerization of styrene has been carried out with VCl₄–AlEt₃ and VCl₄–Al(i-Bu)₃ catalyst systems. These two systems have been found to behave in a similar manner but their behavior is different from those systems where VOCl₃ has been used instead of VCl₄. Reaction is first order with respect to monomer concentration for both the systems and first order with respect to catalyst in the case of VCl₄–AlEt₃. In the case of VCl₄–Al(i-Bu)₃, the rate of polymerization is independent of catalyst concentration but intrinsic viscosities increase with increasing catalyst concentration. The average valence of vanadium in the catalyst complexes has been discussed in relation to nature of catalyst sites. Activation energy and effect of diethyl zinc support the anionic mechanism for the two systems.     

Construction of Improved Stress-Energy Tensor in d ≥ 2

The weakest set of necessary and sufficientconditions for the existence of a conserved tracelesssymmetric stress-energy tensor for a scale-invariantPoincare field theory over a d-dimensional flatspace-time manifold has been proved. This improved tensoris explicitly constructed for arbitrary space-timedimensions including d = 2. The example of a vectorfield in d 3, d 4 demonstrates that fullconformal symmetry over a flat space-time is sufficientbut not necessary for the existence of an improvedtensor.     

Mixed ligand complexes of manganese(III) with dithiocarbamate and glycine/acetylacetone ligands: magnetic,spectral and thermal studies

Summary Mixed ligand complexes of Mn^III with morpholyl and piperidyldithiocarbamates (A) and glycine/acetylacetone (A) have been prepared with the general formule MnAA₂, MnA₂A and Mn(A)₃, and have been characterised by elemental analysis, magnetic susceptibility measurements, i.r. electronic and e.s.r. spectral techniques and by thermal analysis. The complexes exhibit magnetic moment in the 4.5–5.3 B.M. range. The ligands are bidentate. E.s.r. studies suggest that all the complexes have six-coordinate actahedral geometry. T.g.a. studies reveal one step decomposition of complexes and formation of manganese dioxide.     

4,4′-Bipyridyl complexes of iron: Magnetic,Mössbauer and other spectroscopic studies

Summary 4,4-Bipyridyl (4,4-bipy) complexes of ferrous salts of the Fe(4,4-bipy)_x(anion)_y type (where x or y=1 or 2) and of ferric salts of the Fe(4,4-bipy)_m(anion)_n type (where m=1 or 2 and n=3) have been synthesised. Elemental analyses, i.r. and electronic spectra, magnetic and Mössbauer studies have been performed to characterize the complexes. 4,4-Bipy and some anions are inferred to act as bridging ligands. The magnetic moments, electronic and Mössbauer spectra suggest that the complexes are of high spin type with distorted octahedral structures. The value of the isomer shift and quadrupole splitting are discussed in terms of bonding of the ligand and anions.     

Use of reciprocal temperature rise equation in analysis of non-isothermal kinetic data in general

Theoretical analysis of kinetic data obtained under increasing temperature conditions requires the solution of an exponential integral through various approximations. This paper shows that some common types of temperature variation approximating linear variation can be described, at least in limited temperature ranges, by a reciprocal temperature rise equation of the kind

where T is the absolute temperature, t is time and a and b are constants. Use of this equation leads directly to a simple and exact solution. A set of actual experimental data on the decomposition of CaCO₃ is analyzed to substantiate the approach proposed and demonstrate its usefulness.