Adsorptionschromatographie an Aluminiumoxid

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Improved calculation of field isotope shift constants for optical spectral lines

Following the approach of previous investigations improved formulae for the field isotope shift constantC _unif of optical spectral lines have been derived assuming a uniform nuclear charge distribution. From these formulaeC _unif may be evaluated forselectrons with an accuracy of better than 1%. After considering the effect of the different normalization procedures the results obtained by different methods of approach are in good agreement.     

Die Bestimmung von geringen Mengen Sulfat als Methylenblau

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Bine Mischung von Luminol und Fluorescein

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Zur Trennung von Gasgemischen

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Cumulative "roof effect" in high-resolution in vivo 31P NMR spectra of human calf muscle and the Clebsch-Gordan coefficients of ATP at 1.5 T

NMR spectra of non-weakly coupled spin systems exhibit asymmetries in line intensities known as "roof effect" in 1D spectroscopy. Due to limited spectral resolution, this effect has not been paid much attention so far in in vivo spectroscopy. But when high-quality spectra are obtained, this effect should be taken into account to explain the quantum-mechanical fine structure of the system. Adenosine 5'-triphosphate (ATP) represents a 31P spin system with multiple line splittings which are caused by J-couplings of medium strength at 1.5 T. We analyzed the ATP roof effect in vivo, especially for the beta-ATP multiplet. The intensities of its outer resonances deviate by ca. 12.5% from a symmetrical triplet. As this asymmetry reflects the transition from Paschen-Back to Zeeman effect with total spin that is largely broken up, the Clebsch-Gordan coefficients of the system can be indicated in analogy to the hyperfine structure of hydrogen. Taking the roof effect into account, the chi2 of fitting in vivo ATP resonances is reduced by ca. 9% (p<0.005).