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Introduction

Multidimensional decomposition (MDD) is a mathematical tool for processing 3D or higher dimensionality NMR spectra. For theoretical background, examples and applications, please see the references. For the purposes of this text, it is important to understand that MDD is able to reconstruct a complete spectrum from approximately 30% of FIDs that are actually recorded, the so called sparse or non-uniformly sampled (NUS) spectrum. The program MDDGUI combines a few scripts to prepare the input and process the output of the actual MDD calculation. So far it works only for 3D spectra. The whole process currently has 8 steps as follows

  1. Insert zeros into the Bruker SER or Varian FID file. As we currently use NMRPIPE in some steps of the processing, it is required that the recorded FIDs are placed in their proper positions as if all 100% of the spectrum were recorded, not just the 30%.
  2. Convert the newly produced SER-/FID-style file into NMRPIPE format (BRUK2PIPE or VAR2PIPE).
  3. Find the proper phase corrections in the acquisition (directly detected) dimension by processing the first plane of the spectrum (it is complete for Bruker, but not Varian data sets). Uses NMRPIPE.
  4. Fourier transform the acquisition dimension for the whole spectrum and extract the region to be calculated, e.g. $^{15}$N, aromatic or aliphatic (NMRPIPE).
  5. Convert the newly produced NMRPIPE file into the format understood by MDD software.
  6. Calculate and save the result.
  7. Use the result from step 6 to reconstruct missing data.
  8. Fourier transform the indirect dimensions.


next up previous
Next: Recording the data Up: README Previous: README
Aleksandras Gutmanas 2009-01-26