Peter Malavé | Searcharxiv

arXiv2014

Effects of Phase Cycling on Quantum Coherence Pathways in Satellite Transition Magic Angle Spinning Experiments

Multiple quantum experiments are used to resolve broad peaks in nuclear magnetic resonance spectra of quadrupolar nuclei. In this work, we study phase cycling of radio frequency pulses in a single quantum satellite transition magic angle spinning experiment. The particular pulse sequence is a shifted echo sequence where phases of the pulses are varied in accordance with coherence selection rules. Experiments were performed on a $^{17}$O enriched sample of SiO$_2$. Results show that certain phase sequences may decrease the full width at half maximum of spectral peaks.

quant-ph↗

arXiv2014

Scale Factor Dependencies in Quantum Dipole Coupled Lee-Goldburg Cross-Polarization Experiments

Lee-Goldburg cross polarization is used in many NMR experiments to determine internuclear distances. Distances calculated from frequency peaks in the dipolar coupled dimension are subject to scale factors. Experimentally determined scale factors can differ significantly from the theoreticalyy useful value described in the literature. In this work, simulations using SPINEVOLUTION explore effects of varying experimental parameters of frequency offset and cross polarization powers on $^{15}$N-H systems. Experimental data is used to corroborate the simulation. The scale factor is shown not only to depend on the offset frequency but also the cross polarization powers of the observed nucleus. Scale factors greater than one are shown to be possible in simulated data, though such factors obscure the determination of internuclear distances.

quant-ph↗