Related Experiment Video
Updated: Jul 19, 2026

Hyperpolarized Xenon for NMR and MRI Applications
Published on: September 6, 2012
Sensitivity enhancement of NMR spectra of half-integer spin quadrupolar nuclei in solids using hyperbolic secant
Renée Siegel1, Thomas T Nakashima, Roderick E Wasylishen
1Department of Chemistry, Gunning/Lemieux Chemistry Centre, University of Alberta, Edmonton, Alta., Canada T6G 2G2.
Abstract:
The experimental factors influencing the enhancements achievable for the central NMR transition, m(I)=1/2-->m(I)=-1/2, of spin-3/2 and spin-5/2 nuclei in the solid state using hyperbolic secant, HS, pulses for population transfer are investigated. In the case of powder samples spinning at the magic angle, it is found that the spinning frequency, the bandwidth and the frequency offset of the HS pulse play a crucial role in determining the maximum enhancements. Specifically, the bandwidth must be set to the spinning frequency for maximum signal enhancements. The (87)Rb NMR enhancement obtained for RbClO(4) using HS pulses was relatively insensitive to the magic angle spinning frequency; however, in the case of Al(acac)(3), the (27)Al enhancement increased with MAS frequency. In order to obtain an adiabatic HS sweep, one should optimize the rf field for a given pulse duration or optimize the pulse duration for a given rf field.
More Related Videos
Related Concept Videos
Double Resonance Techniques: Overview
Spin decoupling is usually achieved by...
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
NMR Spectrometers: Resolution and Error Correction
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
NMR Spectroscopy: Spin–Spin Coupling

