Samples of Spectra Obtained During Research:
Vanadyl-trisulphate, in molten potassium pyrosulphate at ca. 400oC. In liquid phase (in aquous as well as in molten salt solutions) isotropic spectra is obtained due to the tumbling-effect:
Vanadyl-trisulphate, similar sample quenched in
ice/water from 450°C. Axial-symmetric spectra:
Determination of the g- and A-values of Vanadyl-trisulphate:
It is possible to determine the characteristic magnetic values of the paramagnetic compound from the axial symmetric spectra. This is done by an iterative procedure published by Chasteen, D. N., Biological Magnetic Resonance, 3, 55, (1981). Input for the iterations are the microwave frequency and the resonance fields for each spin quantum number.
Obtained values:
Simulation of Spectra:
In order to get visual evidence for the the integrety of the calculated values simulated spectra is compared to experimental spectra. The characteristical values are fed to a simulation application. We use Bruker Simfonia.
Simulations:
Line Width Effects:
The type of alkali metal used as cation in the pyrosulphate melt proved to have influence on the linewidth of the axial symmetric spectra. The bigger the ion (Na+, K+, Rb+, Cs+) the broader the linewidth.This is due to collisions of paramagnetic species (spin-spin relaxation). The developement of the the line width is proportional to the volumetric percentage of the alkali ion in the melt. In the figure this is expressed by the term R3/Vm, R being the radius of the cation and Vm the molar volume of the pyrosulphate melt.
