ACCORDION principle

In a 2D experiments a series of FIDs are acquired using an incremented delay tl to build up a 2D data matrix, each row of the matrix corresponding to a specific value of tl. The effect of the incremented delay is to modulate the FIDs from the experiments, which can be interpreted and analysed as a pseudo FID with respect to the time delay tl. By convention the incremented delay is called dO and the increment inO. The detected frequency range in the fl dimension is given by ASW [Hz] = l/(inO ndO ). Normally there is only one time increment variable but in special pulse sequences based upon for instance the ACCORDION-principle, see section 5.9.3, additional increment variable ini, in2... can be defined. Usually for the first experiment dO = 3 us and for the second and subsequent experiments dO = 3u -i- inO (n -1). In a number of 2D experiments the... 

Looking at this second edition in a little more detail chapter 5.3.1 has been extended to include simulations of multiple offset selective pulse experiments whilst chapter 5.5.2 examines ACCORDION-principle based HMBC experiments. Multiple offset selective pulse experiments are now an important application in LC-NMR and biomolecular NMR spectroscopy whilst the discussion of the CIGAR and the IMPEACH-HMBC experiment in chapter 5.5.2 are an invitation to use NMR-SIM to trace complex pulse sequences back to their origin. There is now a more comprehensive discussion of filter elements, which are now a vital element in the latest pulse sequences, in chapter 5.8.2. Finally the new chapter 5.9 is subdivided into two subsections. The first subsection 5.9.1 is a collection of some of the latest published ideas to improve existing sequences. Section... 

A somewhat similar to the above, but this time with the quadrature detection with sensitivity enhancement, was used by Ding and Gronenborn to measure different coupling involving back-bone nuclei. In one version of the method the J-evolution was introduced into 2D [ H, N]-HSQC-like spectrum by synchronising it with the chemical shift using the accordion principle. The... 

Principles of the Method. The method is based on the mixed echo composed of the Hahn and the magic echo (33,71,72). The Hahn echo explores the magic echo shape generated by an accordion magic sandwich (cf Fig. 7). 

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