Absolutbestimmung der austrittsarbeit von palladium mit einem röntgenphotoelektronenspektrometer

Based on the work of Ascarelli and Missoni⁴ and Evans¹ a method for absolute measurements of work-functions of electrically conductive samples is developed which is applicable to instruments without retarding field and with a spherical analyzer. The calibration of the instrument, as well as the determination of the onset of the secondary electron spectrum and the Fermi-level, are discussed. For a polycrystalline palladium platelet with an argon-ion cleaned surface, a work-function ofW′_Pd = 4.5(4) ± 0.2(0) eV has been obtained, which agrees with the literature value³ of 4.64 eV within the range of accuracy.     

Calorimetrie

Ohne Zusammenfassung     

Manometer

Ohne Zusammenfassung     

EPR and ENDOR investigations of Ge,Sn and Pb impurities in CdSe

Electron paramagnetic resonance (EPR) experiments of light activated Ge, Sn and Pb impurities in wurtzite type CdSe crystals are presented. These²S_1/2 centres exhibit a large hyperfine structure which shows a variation with temperature. 25 shells of neighbour nuclei are resolved for CdSeSn by means of the Electron nuclear double resonance (ENDOR) technique. All shells belong to one of three distinct shell symmetries of the lattice thus confirming a high symmetry defect. Additional Sn respectively Ge related spectra are described and interpreted as complex centres correlated with lithium.     

Gold catalysis: non-spirocyclic intermediates in the conversion of furanynes by the formal insertion of an alkyne into an aryl-alkyl cc single bond

It takes al-kynes: The formation of furyl-substituted heterocycles from furanynes with donor groups on the furan-alkyne tether and mechanistic control experiments indicate the involvement of open-chained carbenium ions in the overall insertion of an alkyne into a C?C bond, rather than the usual spirocyclic intermediates.     

Ancient DNA profiling by megaplex amplications

Simultaneous amplification of nine human short tandem repeat (STR) DNA sequences and the amelogenin locus allows reducing to an absolute minimum the amount of sample material that is necessary for genetic identification or kinship analysis. Valuable remains can be studied this way without any visible damage, as is demonstrated by typing the DNA of a tooth root from the Saxon warrior Widukind, who died about 1200 years ago. The broad applicability of the megaplex approach is shown by typing bone and teeth specimens ranging from a few months to 3000 years of age employing AmpFlSTR Profiler Plus. Additionally, megaplex STR typing is the method of choice for proving the authenticity of molecular results derived from ancient degraded DNA.     

Aldehyde und Ketone

Ohne Zusammenfassung