Synthese disubstituierter Pyridine über Radikalreaktionen, 2. Mitt.

The synthesis of benzyl and phenethyl substituted 3-pyridine carbonitriles and 3-pyridine carboxylic acid methylesters resp. by homolytic alkylation is reported.     

Absorption line narrowing (A.L.N.) in a three-level system of neon under interaction with two quasi-resonant lasers

We report the observation of Absorption Line Narrowing (A.L.N.) in a Doppler-broadened three-level system of neon under interaction with two quasi-resonant single-mode lasers. The resonance signals are obtained with the laser beams propagating either in the same direction or in opposite direction. The resonance width is found to be smaller in the latter case. The isotopic shifts ²²Ne-²⁰Ne of the lines λ = 1.15μ, λ = 6096 Å and λ = 5945 Å have been measured using the A.L.N. method.     

Microscopic theory of dispersive transport in disordered semiconductors

A theory of dispersive transport based on the microscopic master equation is presented. The theory agrees with previous approaches and unifies them but is much more general. By means of the two-site effective medium approximation of Movaghar et al. we derive a generalised master equation for the averaged propagator of the carriers the kernel of which can be calculated directly from the microscopic transfer rates and distribution functions. We give analytic expressions for the transient current i(t) including the conditions for the transition from dispersive to Gaussian transport for three relevant hopping models. The influence of multiple trapping is treated by means of the coherent potential approximation. We find the same results for trapping with an exponentiak trap depth distribution and fixed-range hopping over energy barriers with an exponential barrier height distribution.     

Absorption spectra of dysprosium compounds in nonaqueous solutions. Spectral intensity analysis

Absorption spectra of dysprosium compounds were measured in amides and D₂O within the 5500–35000 cm^?1 region and in alcohols within the 7000–34300 cm^?1 region. The oscillator strengths of f-f absorptions bands below 35000 cm^?1 were determined. The intensities of the Dy³⁺ ground state absorption were analyzed according to the Judd-Ofelt theory of forced electric dipole transitions.A good fit to the measurements was obtained with the intensity parameter given in Tables 4–6. The polarizability effect on the intensity of the f-f transition with high value matrix elements U⁽⁴⁾ and U⁽⁶⁾ were considered.     

On the divisor class groups of localizations,completions and veronesean subrings of z-graded krull domains

Summary LetR be aZ-graded, noetherian, integral domain. This paper deals mainly with the divisor class groups of localizations and completions with respect to an α-adic topology (α homogeneous) ofR. Some technical results are used to study the Veronesean subrings ofR.

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Riassunto SiaR un dominioZ-graduato, noetheriano. Questo articolo tratta principalmente il gruppo di classi di divisori di localizzazioni e completamenti rispetto ad una topologia α-adica (α omogeneo) diR. Alcuni risultati tecnici vengono applicati allo studio dei sottoanelli Veronesiani diR.