GARP pulse sequence

Fig. 1. Pulse sequence for the X/Y H PFG-HSQC experiment as employed for 19F/13C correlation spectroscopy in Ref. 21. 90° and 180° hard pulses are denoted by solid and open bars, respectively groups of two solid and one open bars denote 90° 0 — 180° +9o — 90° pulse sandwiches that serve as composite 180° pulses. 2 are delays of length 1 /(2 Jx,v), and r is a short delay of the same length as the gradient pulse (typically 1 ms). Phase cycles are as in the standard HSQC experiment, and the ratio of gradient pulse strengths is set to G2/G1 = Yy/Yx- Decoupling is employed using WALTZ-16 ( H) and GARP (Y) pulse trains.

Other strategies to achieve this task are provided by the broadband (BB) saturation sequences (like MLEV16 (Fig. 9.1J) [21], WALTZ16 [22], GARP [23], DIPSI [24], etc.). The power of the BB saturation pulse can be adjusted in such a way as to effectively saturate the slowly relaxing signals and only maiginally the... 

The 180° 13C pulse at the middle of the evolution period interchanges the precession frequencies of the a and /3 spins (see Fig. 9.2, bottom) and effectively decouples the spins during tu and a broadband decoupling sequence, such as WALTZ or GARP, is applied during f2.Thus, the 13C spectrum in the F2 dimension is decoupled, and the H spectrum in the Fx dimension retains homonuclear couplings but is also decoupled from 13C, as illustrated in Fig. 10.106. 

HMQC). The initial part of the sequence, labeled BIRD, is a pulse scheme for removing from the spectrum the H resonances of protons attached to nuclei. The filled symbols denote 90° pulses and the open symbols denote 180° pulses, x, y, and 0 refer to RF pulse phases. The delay A is set to 1/(2 x u/ch)- GARP denotes a pulse method of spin decoupling all nuclei. 

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