The diagram to the below provides an introduction as to some of the interesting phenomena occurring during a90°-90°-echo sequence. The first two drawings in the left column show the expected effect of the initial90°-pulse and T2*-dephasing. For illustrative purposes we have selected four sp...
The Hahn-echo sequence is then used to obtain the quadrupole coupling constant and asymmetry parameter on a powder sample of Co 4 (CO) 12 . This technique is found to be particularly useful when the NMR spectrum is broad and featureless.Pierre Kempgens a...
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掳 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. ...
echo "There are `who | wc -l` userids logged in right now." For example, if 5 people are logged in, you will see: There are 5 userids logged in right now. If you share a multiuser system, this is an interesting command to put in your login file (see Chapter 14). Jump...
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)...
In the absence of an NH group, the coupling constants 1J(29Si 15N) were measured from the 15N satellites in 29Si NMR spectra recorded by using the Hahn-echo extended (HEED) refocused INEPT pulse sequence. Isotope induced chemical shifts 1Δ 15/14N(29Si) were also measured by this ...
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 ...
NMR line breadthorganic compounds/ P-N bonded compoundssignal suppressionHahn-echo extended pulse sequencesN-pyrrolyl-phosphorus compounds31P NMR signalsscalar relaxationNot Availabledoi:10.1006/jmra.1994.1054B. WrackmeyerG. KehrJournal of Magnetic Resonance...
spin echo (NMR)/ Hahn-echoes14Nsolidsstray-field methodimaginglong echo-train summationPowles-Mansfield pulse-sequencesWe have observed Hahn-echoes resulting from Powles-Mansfield pulse-sequences for a variety of nitrogen containing solids which exhibit a range of 14N electric quadrupole coupling ...