Kinetic data are reporled for the halogenation of the first five members of the fatty acid series. The influence of substitution of electron withdrawing and electron releasing group in the methyl radical of acetic acid was studied in solution. The mechanism of the reaction has been discussed. Uber
Magnetic field effects on photoluminescence in PPP. Investigation of the influence of chain length and degree of order
β Scribed by E.L. Frankevich; G.E. Zoriniants; A.N. Chaban; M.M. Triebel; S. Blumstengel; V.M. Kobryanskii
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 448 KB
- Volume
- 261
- Category
- Article
- ISSN
- 0009-2614
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β¦ Synopsis
The effect of weak static magnetic fields on the photoluminescence quantum yield in poly(para-phenylene) films, which differ in chain length and degree of crystallinity, were investigated in the temperature range between 100 and 300 K. Applying a magnetic field enhances the photoluminescence quantum yield, the relative photoluminescence increase being about a factor 10-4. On the basis of the magnetic field sensitivity, it is proposed that the emission of photoluminescence is partially due to geminate recombination of charge carriers. The formation of intermediate charge transfer states after photoexcitation is responsible for the appearance of the magnetic field effect. Properties of these states are investigated in terms of magnetic field effects, and the influence of the structure of the polymer films is discussed.
π SIMILAR VOLUMES
## Abstract Diβ__n__βalkyl substituted polyfluorenes with alkyl chain lengths of 6, 7, 8, 9, and 10 carbon atoms (PF6, PF7, PF8, PF9, and PF10) are studied in dilute solution in MCH using optical spectroscopy. Betaβphase is formed upon cooling in solutions (βΌ 7βΒ΅g mL^β1^) of PF7, PF8, and PF9 only,