Gaussian pulse cascades

In Check it 5.3.1.4 the x- and y-profiles of the transverse magnetization for a 270° Gaussian pulse [5.91], a 90° half-GAUSSiAN pulse [5.92] and a 90° Gaussian Pulse Cascade G4 [5.93] are compared. Finally the H spectra of dibromopropionic acid with selective excitation of the proton at 2.85 ppm is simulated for all three shaped pulses. 

Hz (270° Gaussian pulse),. .. wave halfg128.shp and 17.5 Hz (90° Half-Gaussian pulse),. .. wave gcas128.shp and 139 Hz (90° Gaussian Pulse Cascade). Process the FIDs (Si(r+i) 64k, wdw EM, LB 1.0 [Hz]) and compare the profiles for the phase alternation from a positive to a negative offset frequency. 

Gaussian pulse cascade [5.93.5.95] GCAS 128 Rectangular pulse [5.96] RECT... 

Emsley L, Bodenhausen G (1990) Gaussian pulse cascades - new analytical functions for rectangular selective inversion and in-phase excitation in NMR. Chem Phys Lett 165 469 76... 

Fig. 1. Computer simulations of four selective excitation pulses. (Top) Pulse shapes. From left to right 90° rectangular pulse, 270° Gaussian truncated at 2.5%, Quaternion cascade Q, and E-BURP-1. The vertical axis shows the relative rf amplitudes, whereas the horizontal axis shows the time. (Middle) Trajectories of Cartesian operators in the rotating frame...

Fig. 4. Numerical simulations showing the effect of 20% miscalibration of the rf amplitudes of two selective excitation pulses (Top) A 270° Gaussian of 30 ms duration (peak amplitudes from left to right 43 Hz, 54 Hz, and 65 Hz) and (Bottom) a Quaternion cascade of 30 ms duration (peak amplitudes from left to right 121 Hz, 151 Hz, and 181 Hz). The multiplets were obtained by simulating a three-spin system with couplings Jam = 7 Hz, Jax = 12 Hz, and Jmx = 0 Hz. The vertical axes show a constant arbitrary amplitude, whereas the horizontal axis gives the frequencies 1 a 50 Hz.

Figure 7.18. Traces from the 2D absorption-mode 7-resolved spectrum of menthol 7.1. (a) A region from the ID proton spectrum, (b) the 02 projection of the titled 2D spectrum showing proton-decoupled resonances and (c) the corresponding traces through the/i multiplets in the 2D spectrum. The multiplets for protons 3 and 4 are not fully decoupled for reasons described in the text. The data were acquired with a total acquisition time of 1 s in both t2 and fi using a 60Hz/i window. The selective 180° pulse was a 50 ms Q3 Gaussian cascade, and the gradient strength was 1% of the maximum 53 G cm 0 The broadband 180° pulses were BIPs (720.50.20) applied for 100 Xs at a Bi field strength of 20 kHz.

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