title: Efficient heteronuclear decoupling in MAS solid-state NMR using non-rotor-synchronized rCW irradiation.
abstract: We present new non-rotor-synchronized variants of the recently introduced refocused continuous wave (rCW) heteronuclear decoupling method significantly improving the performance relative to the original rotor-synchronized variants. Under non-rotor-synchronized conditions the rCW decoupling sequences provide more efficient decoupling, are easier to setup, and prove more robust towards experimental parameters such as radio frequency (rf) field amplitude and spinning frequency. This is demonstrated through numerical simulations substantiated with experimental results under different sample spinning and rf field amplitude conditions for powder samples of U-(13)C-glycine and U-(13)C-L-histidine·HCl·H2O.
authors.affiliation: Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
authors.forename: Asif
authors.initials: A
authors.lastname: Equbal
authors.affiliation: Department of Chemistry, Center for Excellence in Basic Sciences, University of Mumbai and Department of Atomic Energy, Health Centre, University of Mumbai, Vidhyanagari Campus, Mumbai 400098, India.
authors.forename: Subhradip
authors.initials: S
authors.lastname: Paul
authors.affiliation: Department of Chemistry, Guru Nanak Dev University, Amritsar 143005, India.
authors.forename: Venus Singh
authors.initials: VS
authors.lastname: Mithu
authors.affiliation: Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India; TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India. Electronic address: madhu@tifr.res.in.
authors.forename: P K
authors.initials: PK
authors.lastname: Madhu
authors.affiliation: Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark. Electronic address: ncn@inano.au.dk.
authors.forename: Niels Chr
authors.initials: NC
authors.lastname: Nielsen
keywords: Heteronuclear dipolar decoupling; Magic-angle spinning; Non-rotor-synchronization; Solid-state NMR; rCW decoupling