Study of thermal stresses in monocrystals Hg2Cl2, PbCl2 during solidification

The method and results of the calculation of the thermal stresses in Hg₂Cl₂ and PbCl₂ monocrystals during crystal growth process are presented. The experimental technique is shown which enables us to minimize the nonlinearity of temperature distribution in crystals.     

On the question of Bi(III) complexes in NaCl

The absorption of trivalent bismuth in solutions of sodium chloride of different concentrations was studied. The absorption bands were ascribed to complexes of bismuth with chlorine. The agreement between absorption bands in NaCl and KCl crystals doped with bismuth and in sufficiently concentrated solutions shows that bismuth in these crystals forms an octahedral complex with six neighbouring chlorine ions.     

Das elektrische und optische Verhalten der Kristalle von NaCl mit Calcium. I

Zusammenfassung Die in dieser Arbeit enthaltenen Ergebnisse betreffend die auf verschiedene Weise zubereiteten Kristalle von NaCl mit Calciumzusatz sind im Abschnitt 3.1 unter den Punkten a) bis e) und im Abschnitt 3.2 unter den Punkten a) bis d) zusammengefaßt. Im Abschnitt 4 wurden vier Möglichkeiten für die Erklärung des unterschiedlichen Verhaltens der Kristalle von NaCl-Ca gezüchtet aus der Schmelze bzw. aus der Lösung diskutiert. Als am wahrscheinlichsten erscheint die unter d) angeführte Möglichkeit, daß nämlich das optische und elektrische Verhalten dieser Kristalle vorwiegend durch die Hydrolyseprodukte beeinflußt wird.

---

The paper gives the results of measuring the dielectric losses and thermally stimulated electron emission and luminescence in NaCl crystals doped with calcium. The crystals were prepared both from the melt and from the solution. The influence of annealing either in air or in dry hydrogen chloride was studied of them. A summary of the results is given at the end of the paper.

---

---

Die Verfasser danken den Diplomchemikern M. Lébl und I. Velická-Kunzlová für ihre Hilfe bei der Zubereitung der Proben und K. Listoová für die sorgfältige Durchführung der Versuche und für die Hilfe bei deren Auswertung.     

Observation of in-medium modifications of the omega meson

The photoproduction of omega mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the omega meson via the reaction gamma + A --> omega + X --> pi(0)gamma + X('). Results obtained for Nb are compared to a reference measurement on a LH2 target. While for recoiling, long-lived mesons (pi(0), eta, and eta;(')), which decay outside of the nucleus, a difference in the line shape for the two data samples is not observed, we find a significant enhancement towards lower masses for omega mesons produced on the Nb target. For momenta less than 500 MeV/c an in-medium omega meson mass of M(medium) = [722(+4)(-4)(stat)+35-5(syst)] MeV/c(2) has been deduced at an estimated average nuclear density of 0.6rho(0).     

Selective N-debenzylation of benzylamino derivatives of 1, 6-anhydro-beta-D-hexopyranoses

When the series of 2-, 3-, and 4-(benzylamino)-2-, 3-, and 4-deoxy derivatives of 1,6-anhydro-beta-D-hexopyranoses in the D-gluco, D-lyxo, and D-arabino configurations were reacted with diisopropyl azodicarboxylate, N-benzyl groups were selectively cleaved in the presence of O-benzyl groups. The yields ranged from 51 to 97%. The debenzylation of some aliphatic benzylamines is also discussed.     

Electron spin density distribution in the polymer phase of CsC60: assignment of the NMR spectrum

We present high resolution 133Cs-13C double resonance NMR data and 13C-13C NMR correlation spectra of 13C enriched samples of the polymeric phase of CsC60. These data lead to a partial assignment of the lines in the 13C NMR spectrum of CsC60 to the carbon positions on the C60 molecule. A plausible completion of the assignment can be made on the basis of an ab initio calculation. The data support the view that the conduction electron density is concentrated at the C60 "equator," away from the interfullerene bonds.