Design of high-power, broadband 180° pulses and mixing sequences for fast MAS solid state chemical shift correlation NMR spectroscopy
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An approach for the design of high-power, broadband 180° pulses and mixing sequences for generating dipolar and scalar coupling mediated 13C–13C chemical shift correlation spectra of isotopically labelled biological systems at fast magic-angle spinning frequencies without 1H decoupling during mixing is presented. Considering RF field strengths in the range of 100–120 kHz, as typically available in MAS probes employed at high spinning speeds, and limited B 1 field inhomogeneities, the Fourier coefficients defining the phase modulation profile of the RF pulses were optimised numerically to obtain broadband inversion and refocussing pulses and mixing sequences. Experimental measurements were carried out to assess the performance characteristics of the mixing sequences reported here.
KeywordsDipolar Coupling Inversion Pulse Chemical Shift Correlation Refocus Pulse Adiabatic Inversion Pulse
This study has been funded in part by a grant from the Deutsche Forschungsgemeinschaft (GO474/6-1). The FLI is a member of the Science Association “Gottfried Wilhelm Leibniz” (WGL) and is financially supported by the Federal Government of Germany and the State of Thuringia. We would like to thank the referees for their useful comments on the original manuscript.
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