Decoupler modulation parameter

In Section 2-4, we encountered a number of spectral acquisition parameters. The selection of these parameters is relatively direct and straightforward, with the exception of the flip angle a and the decoupler modulation frequency (for WALTZ decoupling). Neither a nor the decoupler modulation frequency is entered directly, and both parameters require that the spectrometer be calibrated. 

The Varian parameter dmm determines whether the decoupler output is a simple continuous irradiation (dmm = c ) or a pulsed waltz-16 modulation (dmm = w ). For nonselective ( broadband ) decoupling such as that desired for a ID 13C spectrum, the waltz-16 mode is... 

For DSSCs to be marketable and to compete with their inorganic counterparts, fundamental science has to be used to find ways of enhancing cell and module life time and stability without sacrificing performance and scalability. These cells possess a complex structure with disparate materials. Predictive models, validated and improved by cmitinuous feedback from experimental measurements, are needed to decouple and study the many competing mechanisms found in the working cell. With this tool we can discover how cell performance and cell design are related to its material parameters and then systematically search for and arrive at the design specifications that will optimize the cell operation. The need for systematic researeh in DSSC has been stressed by Peter [9]. 

NMR can, in principle, provide complementary information on motional processes in liquid crystals. The dipole-dipole interaction between a C-H pair and the quadrupolar interaction when the proton is replaced with a deuteron share the same principal interaction axis. In the case where the carbon is not directly bonded to a proton, there is still dipole-dipole relaxation by nearby protons, but it is also necessary to include an additional relaxation mechanism, the modulation of the chemical shift anisotropy. Proton spin decoupling is necessary to give well-resolved chemically shifted lines in the mesophase of liquid crystals. Furthermore, it is not practical to determine individual spectral density parameters from measured relaxation rates. Proton-proton dipolar interactions may not be ignored even when observation is exclusively confined to the resonant spin [5.31]. This is because proton relaxation causes population flow among the proton spin levels through dipolar (or scalar) coupling. As a consequence, cross-... 

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