Two photon ionization of rubidium

Using the implicit summation technique, the parameters of two-photon ionization of rubidium by the second harmonic of ruby laser are reported. The Hartree-Fock and Hartree-Fock-Slater wavefunctions have been used and the spin-orbit perturbation has been included.     

Ion-exchange of some elements in limestone, dolomite and chrome-iron ore

An ion-exchange procedure is described for the analysis of dolomite, limestone and chrome-iron ore. In dolomite and limestone, calcium and magnesium are separated by eluting with 1M acetate buffer (pH 6) ; in chrome-iron ore, chromium(VI) is first separated from other metals by passage through a cation-exchanger, Dowex 50W-X8 (H+ form), when chromium(VI) is not adsorbed. Iron, aluminium and magnesium are subsequently recovered from the resin and are determined by conventional methods.     

Spectrophotometric determination of fluoride a comparative study and a suggestion for evaluating photometric data

Summary Attempts were made to develop a method for fluoride determination using the demasking principle; the result was negative. Using the method of bleaching, ferric-sulfosalicylate, ferric-tiferronate, titanium-chromotropic acid and zirconium-alizarin coloured systems have been thoroughly investigated and compared for use as reagents for fluoride determination. Ferric-sulfosalicylate system has been proved to be the best. A new method of comparing photometric data has been suggested. Error in fluoride determination by ferric-sulfosalicylate method according to the method calculation suggested is between 1.80 percent and 4.60 percent, when the fluoride concentration is from 16 to 40 ppm. The method gives reproducible results when the fluoride concentration is in the range of 0.8 ppm to 4.0 ppm.     

A new spot test for palladium

A new Spot test foi palladium is based upon the formation of an orange-yellow chelate with phenyl-α-pyridyl ketoxime Interference by the metals usually associated with palladium can be easily and completely prevented. Lumit of identification 0 5μg Pd     

Complexometric titration of copper (II) using chromotropic acid dioxime as a metal indicator

Summary Chromotropic acid dioxime forms purple coloured complexes with copper in the p_H ranges 5.82 to 6.45 and 7.25 to 8.05 respectively which are less stable than the Cu^II-EDTA complex. On titrating these solutions with EDTA, the purple coloured complexes turn colourless or yellow at the end point. These titrations give satisfactory results in the temperature ranges 20 to 70° C and 20 to 50° C respectively. In acid medium, the titration of copper can be carried out in the presence of magnesium and alkaline earths, but zinc, cadmium, nickel, cobalt, aluminium and iron(III) interfere. The latter two elements can be masked by sodium fluoride. In ammoniacal medium, zinc, cadmium, cobalt, nickel, lead, magnesium and alkaline earths interfere.

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Zusammenfassung Chromotropsäuredioxim bildet mit Kupfer im p_H-Bereich 5,82 bis 6,45 und 7,25–8,05 purpurrot gefärbte Komplexe, die weniger stabil sind als der Kupfer-ÄDTA-Komplex. Bei der Titration solcher Lösungen mit ÄDTA ergibt sich am Endpunkt ein Farbumschlag nach Farblos bzw. Gelb. Bei Temperaturen von 20–70°C bzw. 20–50°C werden gute Ergebnisse erzielt. Die Kupferbestimmung in saurem Medium kann in Gegenwart von Magnesium und Erdalkalien durchgeführt werden; Störungen werden verursacht durch Zink, Cadmium, Nickel, Kobalt, Aluminium und Eisen(III), wobei die beiden letzten jedoch mit Natriumfluorid maskiert werden können. Die Titration in ammoniakalischem Medium wird durch Zink, Cadmium, Kobalt, Nickel, Blei, Magnesium und die Erdalkalien gestört.

     

Free-electron model for the inelastic collision of fast electrons with benzene

Using a free-electron wave function the cross section for the excitation of the first excited state and that for the ionization of benzene in the inelastic collision with fast electrons have been estimated. In the ionization process the cross section has been found to be maximum when the secondary electron moves away with a kinetic energy of about 3 eV. For incident-electron energy above 20 eV the cross section for ionization is larger than that for excitation, while below it the reverse is the case.     

Modulational instability in the presence of Langmuir turbulence

We investigate the effect of high frequency short wavelength Langmuir turbulence on parametrically driven modulational instabilities and find that turbulence reduces their threshold for excitation. We also find an interesting modification of the modulational stability of the Langmuir plasmons due to the presence of the pump wave.