In general, if the first RF-pulse has flip angle α1 and the second has flip angle α2, the maximum signal intensity of the Hahn echo will be smaller than the conventional (90°-180°) echo by a factor of (sin α1)•(sin² α2/2).The...
Application of Hahn-Echo Extended Pulse Sequences to N-Pyrrolyl-Phosphorus CompoundsPractical, Experimental/ chemical shiftisomerismisotope effectsNMR line breadthorganic compounds/ P-N bonded compoundssignal suppressionHahn-echo extended pulse sequences...
Ultra-fast multi-section MRI using gradient and spin echo (GRASE) imaging Fast magnetic resonance imaging uses combined gradient echoes and spin echoes. In each of one or more TR intervals, after an initial NMR RF nutation pulse, a sequence of 180° RF nutation pulses is used to refocus the...
In Figs. 1.34 and 1.35 we show the pulse sequences for 1H and 13C nuclei and the behavior of the magnetization vectors in the cross-polarization experiment, the goal of which is to create a time dependence of the spins that is common to the two rotating frame systems of 1H and 13C. ...
Hahn-echo extended (HEED) pulse sequences in one- and two-dimensional experiments were successfully applied to phosphorus–nitrogen compounds with two PN bonds {2-chloro-1,3-dimethyl-1,3,2-diazaphospholidine (1), 2-tert-butyl-1,3-dimethyl-1,3,2-dizaphospholidine (2), bis(diethylamino)...
Coupling constants 2J(15N13CR) and nJ(15N1HR) in 2-substituted pyridines [R = Me (1), CH=CH2 (2), C≡CH (3), C(O)H (4), C(O)Me (5)] have been measured by using Hahn-echo extended (HEED) pulse sequences for one- (1 D) and two-dimensional (2D) 13C/1H NMR (HEED...
Passive observation of 15N satellites in two‐dimensional heteronuclear X–1H shift‐correlated spectra via a Hahn spin–echo extended pulse sequence13C, 29Si, 119Sn 207Pb and NMR1H?X shift‐correlated two‐dimensional NMR1J(15N, X), 3J(15N, 1H)...
In a spin-correlated radical pair system, anomalous pulse-angle and phase dependence of electron spin echo and multiple-quantum echoes were theoretically calculated by Tang et al. (J. Chem. Phys. 106 , 7471 (1997)). The maximum intensity of the out of phase signal at 45 degree of spin ...
Muneki OhuchiMasami HosonoKazuhiro MatushitaMamoru ImanariElsevier Inc.Journal of Magnetic ResonanceM. Ohuchi, M. Hosono, K. Matushita, and M. Imanari, A new pulse sequence in two—dimensional FT NMR. Solvent elimination using a Hahn echo, J. Magn. Resonance 43 , 499 (1981)....
Heteronuclear Decoupling under Fast MAS by a Rotor-Syncronized Hahn-Echo Pulse Train. J Mag Res. 2005; 176 :239–243.X. Filip, C. Tripon and C. Filip. Heteronuclear decoupling under fast MAS by a rotor-synchronized Hahn-echo pulse train. J. Magn. Reson. 176 (2005) 239-243....