title: Broadband excitation and indirect detection of nitrogen-14 in rotating solids using Delays Alternating with Nutation (DANTE).
abstract: A train of short rotor-synchronized pulses in the manner of Delays Alternating with Nutations for Tailored Excitation (DANTE) applied to nitrogen-14 nuclei (I=1) in samples spinning at the magic angle at high frequencies (typically νrot=62.5 kHz so that τrot=16 μs) allows one to achieve uniform excitation of a great number of spinning sidebands that arise from large first-order quadrupole interactions, as occur for aromatic nitrogen-14 nuclei in histidine. With routine rf amplitudes ω1(14N)/(2π)=60 kHz and very short pulses of a typical duration 0.5<τp<2 μs, efficient excitation can be achieved with 13 rotor-synchronized pulses in 13 τrot=208 μs. Alternatively, with 'overtone' DANTE sequences using 2, 4, or 8 pulses per rotor period one can achieve efficient broadband excitation in fewer rotor periods, typically 2-4 τrot. These principles can be combined with the indirect detection of 14N nuclei via spy nuclei with S=½ such as 1H or 13C in the manner of Dipolar Heteronuclear Multiple-Quantum Correlation (D-HMQC).
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Veronika
authors.initials: V
authors.lastname: Vitzthum
authors.forename: Marc A
authors.initials: MA
authors.lastname: Caporini
authors.forename: Simone
authors.initials: S
authors.lastname: Ulzega
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Bodenhausen
mesh_terms: D002138:Calibration; D003460:Crystallization; D005998:Glycine / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009584:Nitrogen / Q000032:analysis*; D009587:Nitrogen Isotopes
chemical_list: D009587:Nitrogen Isotopes; D006639:Histidine; D009584:Nitrogen; D005998:Glycine