Generalized quantum mechanical two-centre problems

Correlation diagrams for the lowest electronic states of the systems (LiH)³⁺, (HeH)⁺⁺, (LiHe)⁴⁺, H ₂ ⁺ , (He, –1), and (H, –1)^– (finite dipole with one electron) have been computed exactly and are discussed with special regard to the non-crossing rule and to the asymptotic behaviour of generalized diatomic orbitals.

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Zusammenfassung Korrelationsdiagramme für die tiefsten elektronischen Zustände der Systeme (LiH)³⁺, (HeH)⁺⁺, (LiHe)⁴⁺, H ₂ ⁺ , (He, –1) und (H, –1)^– (endlicher Dipol mit einem Elektron) wurden exakt berechnet und werden im Hinblick auf die Nichtüberschneidungsregel und auf das asymptotische Verhalten verallgemeinerter zweiatomiger Bahnfunktionen diskutiert.

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Résumé On a calculé exactement les diagrammes de corrélation pour les plus bas états électroniques des systèmes (LiH)³⁺, (HeH)⁺⁺, (LiHe)⁴⁺, H ₂ ⁺ , (He, –1) et (H, –1) (dipole fini à 1 électron). La discussion porte plus spécialement sur la loi de non-intersection et sur le comportement asymptotique des orbitales diatomiques généralisées.

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Dedicated to Prof. Dr. Hermann Dänzer on occasion of his 65 th birthday on October 21 st.

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The authors express their thanks to the Deutsche Forschungsgemeinschaft for financing computer time on the IBM 7094 and the TR 440 of the Deutsches Rechenzentrum Darmstadt and the CD 3300 of the University of Mainz.     

Recent advances in scanning tunneling microscopy involving magnetic probes and samples

We report on recent developments in the field of STM performed with magnetic probes and samples. The choice of appropriate magnetic sensors and their in situ preparation will be described. We further focus on the information obtained in spin-polarized scanning tunneling microscopy (SPSTM) as well as on possible modes of operation for simultaneous acquisition of topographic and magnetic data. The prospects for SPSTM and related magnetic sensitive SXM techniques will be discussed.Permanent address: Forschungszentrum Jülich, ISI, W-5170 Jülich 1, Fed. Rep. Germany     

Reaction of N-acylthioureas with electrophilic reagents : Synthesis of 1,3,5-oxadiazinium salts, 1,3,5-thiadiazinium salts, 1,2,4-dithiazolium salts and benzothiazoles

N-Acylthioureas 1 can be easily transformed into 2,4-diamino-6-aryl-1,3,5-oxadiazinium salts 12, 2,4-diamino-6-aryl-1,3,5-thiadiazinium salts 13,3-amino-5-aryl-1,2,4-dithiazolium salts 19 and 2-acylimino-benzothiazolines 22, respectively by reaction with different electrophiles. The structure of the compounds prepared is confirmed by analytical data as well as by chemical transformations.     

Gas-liquid chromatography reference method for the assay of urinary creatinine

The gas-liquid chromatographic measurement of urinary creatinine described in this paper employs methylation, the use of a diethylene glycol succinate stationary phase, an internal L-hydroxyproline standard and a temperature of 180 degrees C. The technique, which is specific and reproducible, is shown to be a reference method providing more precise and reliable results than a conventional colorimetric method. In addition, it can be used as a routine method because of its simplicity.     

Λ, Λ production in e+e− annihilation at 33 GeV centre of mass energy

Performing a PWA of the π^?π^?π⁺ system over the ^?tp/p range 0.2 to 0.4 GeV² we find evidence for a J^P = 0^? ,J^G=1^? meson of mass 1342 ± 20 MeV and width 220 ±70 MeV decaying into ?π. This state is produced by natural parity exchange with a slope similar to that of elastic scattering. It can be interpreted as a radial excitation of the π meson (π′).     

Über den optimalen nachhall in kleinen bis mittelgrossen kirchen

The reverberation times of churches should be longer, for example, than those of theatres or concert halls but they must not be too long. By means of an examination of small and medium sized churches, a relation between measured reverberation times and judgments of acoustical qualities is established in this paper. From this relation, an optimum range of average reverberation times, $\text{T}{}_{\mathrm{m}}$, of unoccupied churches at 500 Hz and 1000 Hz octave bands can be derived as a function of volumes extending from 1000 m³ to 12 000 m³.     

Analytische Probleme bei Untersuchungen von bio-geochemischen Kreisl?ufen am Beispiel der Spurenelemente Zn und As

Ohne Zusammenfassung

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Analytical problems in the investigation of bio-geochemical global cycles shown at the trace elements Zn and As