title: Improved decoupling during symmetry-based C9-TOBSY sequences.
abstract: We show that heteronuclear decoupling during symmetry-based C9 TOBSY sequences can be improved by using phase-alternating pulse sequences (XiX) instead of cw irradiation. The use of XiX sequences makes the optimization of the decoupling rf-field amplitude simpler and lowers the decoupling rf-field requirements to attain a comparable performance. A Floquet analysis of the first-order resonance conditions was used to determine the correct timing of the XiX sequence to avoid interference between the C sequence and the decoupling. The decoupling performance is analyzed analytically using Floquet theory and verified using numerical simulations as well as experimental results.
authors.affiliation: Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland.
authors.forename: Kong Ooi
authors.initials: KO
authors.lastname: Tan
authors.affiliation: Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland.
authors.forename: Ingo
authors.initials: I
authors.lastname: Scholz
authors.affiliation: Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland.
authors.forename: Jacco D
authors.initials: JD
authors.lastname: van Beek
authors.affiliation: Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland. Electronic address: beme@ethz.ch.
authors.forename: Beat H
authors.initials: BH
authors.lastname: Meier
authors.affiliation: Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland. Electronic address: maer@ethz.ch.
authors.forename: Matthias
authors.initials: M
authors.lastname: Ernst
keywords: Decoupling; Magic-angle spinning; Solid-state NMR; TOBSY