Nuclear structure and chemical effects in internal conversion of the 35 keVM1+E2 transition in125Te

The relative conversion line intensities of the 35 keV transition in¹²⁵Te were measured using the 50 cm π√2 iron-yoke magnetic spectrometer. The transition was proved to be ofM1+(8.7±1.5)×10^?4 E2 multipolarity, the magnetic component being affected by the nuclear structure with λ=2.4±1.4. The conversion intensity ratio,0/N ₁ , was determined to be 0.115+0.005 for both Ag¹²⁵ I and Cu¹²⁵ I sources. It is in accordance with previous measurements for the Zn^125m Te and Pb^125m Te sources and differs from those for the^125mTeO₂ and Na₂H ₄ ^125m TeO₆ ones. The conversion coefficients were calculated for 32 configurations of the valence shell of free tellurium atom and ions and were compared with the experimental results.     

Threshold electron impact excitation of Cl2

A high resolution electron impact threshold spectroscopy technique was used to examine the excitation of Cl₂ in the 2–14 eV region. This study complements previous photon absorption and emission measurements, because it is capable of detecting transitions which are optically forbidden. In the region up to 7.5 eV, broad dissociative structures are correlated with optically active valence states, although relative intensities in the threshold spectrum differ considerably and indicate a substantial contribution from the optically forbidden transitions. At 7.46 eV a series of 5 equidistant sharp peaks is detected and interpreted as arising from the² π _g Feshbach resonance, which differs from the ground state positive ion Cl ₂ ⁺ by a pair of Rydberg electrons: (4sσ)². The decay channels responsible for the appearance of the resonance in a threshold spectrum are discussed and it is suggested that they include several valence states of the (2431) and (2341) configurations, whose potential energy curves cross the Cl ₂ ^? ,²π_g curve in the region of energy at which the resonance state is formed. At higher incident electron energies and up to ionisation, Rydberg states predominate, starting with (2430) 4s^3,1 π _g states detected for the first time. The absence of broad peaks above 8 eV and the irregular appearance of Rydberg bands is consistent with the strong Rydberg-valence configuration mixing proposed by Peyerimhoff and Buenker. Where our resolution permits comparison, good general agreement is found with recent synchrotron radiation absorption measurements of optically allowed transitions.     

Analytische Bestimmung von Niob,Tantal, Phosphor,Chlorid und 2,2-Dipyridyl in einigen Komplexverbindungen

Zusammenfassung Die analytische Bestimmung der Metalle, des Dipyridyls und der Chloride in Oxo-chloro-alkoxo-dipyridyl-Komplexverbindungen des Niobs und Tantals wurde beschrieben. Eine modifizierte Methode der Dipyridylanalyse, wie auch der Chloridbestimmung in Gegenwart von Dipyridyl wurde angegeben. Die radiometrische Metallbestimmung in Extraktionsverbindungen von Niob und Tantal mit Di-oktyl-methylenbis-phosphonsäure wurde dargelegt.

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Summary The analytical determination of metals, dipyridyl and chlorides in oxochloro-alkoxo-dipyridyl complex compounds of niobium and tantalum is described. A modified procedure of the dipyridyl analysis and also of the determination of chloride in the presence of dipyridyl is given. The radiometric determination of the metals in extraction compounds of niobium and tantalum with di-octyl-methylene-bis-phosphonic acid is discussed.

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Résumé On décrit le dosage des métaux, du dipyridyle et des chlorures dans les composés complexes oxo, chloro, alcoxo, dipyridyle, du niobium et du tantale. On indique une méthode modifiée pour le dosage de dipyridyle ainsi que pour la détermination des chlorures, en présence de dipyridyle. On décrit le dosage radiométrique des métaux dans les produits d'extraction du niobium et du tantale par l'acide di-octyl-méthylène-bis-phosphonique.

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Vorgetragen beim Symposium für analytische Chemie in Graz, 29. September bis 1. Oktober 1965.     

Kinetic determination of ultramicro amounts of copper

A new catalytic reaction is proposed and a kinetic method developed for the determination of ultramicro amounts of Cu(II) on the basis of its catalytic activity in oxidation of the 2-thiosemicarbazone of sodium 1,2-naphthoquinone-4-sulphonate by hydrogen peroxide in the presence of ascorbic acid. Under optimal conditions the sensitivity of the method is 0.25 ng/ml. The relative error is 4.8-18.2% for the concentration range 5-0.8 ng/ml. Most foreign ions do not change the rate of the catalysed reaction. Co(2+) and I(-) catalyse the reaction, Ni(2+) extensively inhibits it, and in the presence of EDTA only the uncatalysed reaction takes place.     

Disposable multichannel immunosensors for 2,4-dichlorophenoxyacetic acid using acetylcholinesterase as an enzyme label

An improved version of the disposable multichannel immunochemical biosensor for the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) based on a screen-printed amperometric transducer and monoclonal antibodies (MAb) against 2,4-D is reported. Entrapment within a thin Nafion film was used for the direct immobilization of MAb at the electrode surface. The amount of the tracer (2,4-D conjugated to acetylcholinesterase) bound in a competitive immunochemical reaction was determined amperometrically using acetylthiocholine iodide as substrate. The measuring procedure (times of incubation with tracer and substrate, pH, tracer concentration) was optimized. The sensor was able to detect less than 0.01 μg/L of free 2,4-D in water. One analysis (8 samples) was completed in 30 min (20 min for immunochemical reaction, 5 min incubation with substrate, 5 min measurement). The performance of the immunosensor (two configurations) was evaluated on real samples (tap water) with added 2,4-D. The determined amounts (mean values 0.097 to 0.105 and 0.89 to 1.13) corresponded well with the added contents of 2,4-D (0.100 and 1.00 μg/L, respectively).     

121Sb-Mössbauer-Spektren von Antimon(V)-Verbindungen. II

¹²¹Sb Mössbauer Spectra of Antimony (V) Compounds. II The Mössbauer resonance effect of ¹²¹Sb has been studied at 4.2 K in a series of 11 antimony(V) compounds which are in most cases bridged. Isomer shift and quadrupole splitting variations are considered in the light of results of X-ray and vibrational spectroscopy. Preparation and the vibrational spectra of [NMe₄][SbCl₄(n₃)₂] are described. Within the limitations of available structural data related tin compounds are compared with those of corresponding ¹¹⁹Sn Mössbauer spectra.     

Sukzessive Minima mit und ohne Nebenbedingungen

Given semi-normsf andg on ⁿ and a real number >0. Then the successive minima off under the constraintg are defined by _j : = inf {: there existj linear independent vectors inZ ⁿ withf andg}. The main theorem of this paper (Lagrange multiplier theorem) states that the successive minima of a certainnorm h on ⁿ (without constraints) coincide with the _j 's up to bounded factors. Moreover, this norm is constructed explicitly. Using Minkowski's wellknown theorem on successive minima and our result certain inequalities on simultaneous Diophantine approximations are derived.     

Analytic expressions for the partial waves of the off-shell two body coulomb T-matrix

Closed form expressions for all partial waves of the pure Coulomb off-shell T-matrix p¦ T_c,l.(k ²) ¦p are obtained. All singularities appear through simple special functions, which makes it possible to study the analytic properties of p¦ T_c,l(k²) ¦p as a function not only of one of the momentap, p but even of both of them. With use of the renormalization procedure found by Zorbas the transition to half-and on-shell values is performed reproducing known expressions. By the same method simple expressions for the partial waves of the Coulomb wave function in the momentum representation are found.     

Periodic,multiplicative number-theoretical functions

D. Leitmann andD. Wolke [3] proved that multiplicative functions, which are restrictions of continuous, periodic functionsF: with irrational period, are constant equal to 0 or 1. In this note a simpler proof for this result is given.     

Production of lepton pairs in processes with hadronic jets

We propose a model for the production of extra (additional) lepton pairs in deep inelastic lepton-hadron scattering, e⁺e^– annihilation and large p_T processes. Extra lepton pairs are supposed to be originated by annihilations of quarks and antiquarks created during the space-time evolution of quark initiated jets. This mechanism yields predominantly dileptons with rather low masses. Predictions following from the model are compared with the recent data on trimuon production in neutrino-nucleon interactions. It is also suggested that internal hard processes can lead to dileptons with both small and large masses. The latter mechanism has rather small cross section but it is particularly interesting from the point of view of the simple quark-parton model.Dedicated to Academician Václav Votruba on the occasion of his seventieth birthday.