title: Quantification and compensation of the influence of pulse transients on symmetry-based recoupling sequences.
abstract: Deviations of amplitude and phase of radio-frequency pulses from the desired values, can have a severe impact on the performance of multiple-pulse sequences in NMR spectroscopy. A particular problem are pulse transients that appear every time there is a discontinuity in amplitude or phase. Based on a Floquet description using pulses with arbitrarily shaped amplitudes and phases we present a systematic study of the influence of pulse transients on symmetry-based pulse sequences in solid-state NMR under magic-angle spinning. This treatment explains the dependence of the experimentally observed transfer efficiency on the details of experimental setups. In addition, three approaches are compared which have the aim to re-establish highly efficient recoupling. We demonstrate that the application of transient-compensated pulses as basic elements of symmetry-based sequences leads to a significantly improved robustness of the experiments with respect to variations in the experimental setup.
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland.
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Wittmann
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland.
authors.forename: Valerie
authors.initials: V
authors.lastname: Mertens
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Takeda
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland. Electronic address: beme@ethz.ch.
authors.forename: Beat H
authors.initials: BH
authors.lastname: Meier
authors.affiliation: Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland. Electronic address: maer@ethz.ch.
authors.forename: Matthias
authors.initials: M
authors.lastname: Ernst
keywords: Linear-response theory; NMR spectroscopy; Pulse transients; Symmetry-based recoupling