DEPT, product operator analysis

To understand the pulse sequence, we will try to get an overview of what is happening and then look at some simplified product operator analysis. Consider first the CH case in the DEPT-90 experiment. Ignoring the 180° pulses, the DEPT-90 sequence can be viewed as an INEPT sequence in which the coherence transfer is split up into two steps (Fig. 7.41) the two 90° pulses are no longer simultaneous and between them we have an intermediate state in coherence transfer multiple-quantum coherence (ZQC and DQC). 

Grossmann et al. used 2D- C, P HETCOR and DEPT spectra to analyse higher-order AA X spin systems in the isotopomers of synunetrical bis-phosphonates with an RO3P-C-C-PO3R backbone. - Based on the known results of a product operator analysis, it was shown that magnitudes and signs (relative to J(P,C) which is positive) of /(P,P) and V(P,C) can be... 

A product operator analysis of the observable coherences for the standard DEPT sequence [5.59] shows that in addition to the wanted coherence Sx (where Sx is the x-component of the S spin product operator and S is the non-abundant 3c spin) several other single quantum coherences are generated. These terms such as I Sx lead to phase distortions in the H coupled spectra because signals which could be assigned to either the Sx or Sy state are overlapped by antiphase signals from coherences like I Sy. Consequently the signal intensity of the related decoupled spectrum is reduced by these coherences. In the DEPT++ sequence only the required single quantum coherences Sx (or... 

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