Synthese von indenothiophenen, 2. Mitt.

The synthesis of 5,6-dihydro-4H-indeno[5,4–b]thiophene (2 b) is described.     

Nerves of simplicial complexes

Aequationes mathematicae -     

Thermoelectric power of TTT2I3+δ

We have measured the thermoelectric power of crystals of TTT₂I_3+δ with conductivity maximum occuring at temperatures from 110 K to 38 K. We find that the metallic state is stabilized to lower temperatures as the samples become less stoichiometric, that the change in electron concentrations on TTT varies by about 5% over this range and that Coulomb correlations are small in this compound.     

Gleichzeitige Messung von Hyperfeinstruktur,Stark-Effekt und Zeeman-Effekt des39K19F mit einer Molekülstrahlresonanzapparatur

An electric Molecular-Beam-Resonance-Spectrometer has been used to measure simultanously the Zeeman- and Stark-effect splitting of the hyperfine structure of³⁹K¹⁹ F. Electric four pole lenses served as focusing and refocusing fields of the spectrometer. A homogenous magnetic field (Zeeman field) was superimposed to the electric field (Stark field) in the transition region of the apparatus. The observed (Δm _J =±1)-transitions were induced electrically. Completely resolved spectra of KF in theJ=1 rotational state have been measured. The obtained quantities are: The electric dipolmomentμ _e l of the molecul forv=0,1 and 2; the rotational magnetic dipolmomentμ _J forv=0,1; the difference of the magnetic shielding (σ_⊥ ? σ_∥) by the electrons of both nuclei as well as the difference of the molecular susceptibility (ξ_⊥ ? ξ_∥). The numerical values are

$$\begin{array}{*{20}c} {\mu _{e1} = 8,585(4)deb,} \\ {\frac{{(\mu _{e1} )_{\upsilon = 1} }}{{(\mu _{e1} )_{\upsilon = 0} }} = 1,0080,} \\ {{{\mu _J } \mathord{\left/ {\vphantom {{\mu _J } J}} \right. \kern-\nulldelimiterspace} J} = ( - )2352(10) \cdot 10^{ - 6} \mu _B ,} \\ {(\sigma _ \bot - \sigma _\parallel )F = ( - )2,19(9) \cdot 10^{ - 4} ,} \\ {(\sigma _ \bot - \sigma _\parallel )K = ( - )12(9) \cdot 10^{ - 4} ,} \\ {(\xi _ \bot - \xi _\parallel ) = 3 (1) \cdot 10^{ - 30} {{erg} \mathord{\left/ {\vphantom {{erg} {Gau\beta ^2 }}} \right. \kern-\nulldelimiterspace} {Gau\beta ^2 }}} \\ \end{array} $$     

Study of electric monopole transitions between the ground state and the first excited 0+ state in 40, 42, 44, 48Ca with high resolution inelastic electron scattering

Monopole transitions from the 0₁⁺ ground states to 0₂⁺ excited states at 3.353 MeV (⁴⁰Ca), 1.837 MeV (⁴²Ca), 1.884 MeV (⁴⁴Ca) and 4.272 MeV (⁴⁸Ca) have been investigated with high resolution inelastic electron scattering (FWHM ≈ 30 keV) at low momentum transfer (0.29 ≦ q ≦ 0.53 fm^?1). The respective monopole matrix elements are 2.53 ± 0.41 fm², 5.24 ± 0.39 fm², 5.45 ± 0.41 fm² and 2.28 ± 0.49 fm². These results are used together with known ground state charge radii and the average number of holes in the sd shell in the ground state to estimate the number of particle-hole excitations in the wave functions of the excited 0⁺ states.     

Interchain interactions and phase transition in NMeQn(TCNQ)2

A sharp non-reversible phase transition is found in the charge transfer salt NMeQn (TCNQ)₂. It is argued that solvent molecules between the chains are responsible for this phase transition, in that, when present they destroy the interchain coupling and lead to effectively decoupled chains in the material. The magnetic and electric properties of both phases are discussed.     

Defect equilibria and conduction mechanisms in ice

Dielectric and elastic relaxation processes in ice may be explained by means of two types of point defects. At the crossover they interchange their roles as majority and minority mechanism. From conductivity measurements at the crossover it is possible to determine the defect mobilities, without knowing the effective charges. Measurements from different laboratories lead to the same results and to the conclusion that in contrast to earlier theoretieal ideas the ion states as such do not play an essential role in the Debye relaxation. The two mechanisms responsible for this process are Bjerrum defects as envisaged in earlier concepts and Bjerrum-ion aggregates. These defects allow an explanation of the temperature dependence of the conductivity in pure and doped ice.