Projections of Cross Peaks

An A-dimensional NMR spectram is spanned by user-defined sweep widths SW, for each of the N dimensions (i = 1N). For a projection spectrum defined by pi, an appropriate sweep width SW needs to be calculated (Fig. 1). Considering that the distribution of chemical shifts in a given dimension is well described by a normal distribution [39], the sweep width can be calculated as [40] 

For an optimal phasing of the projection spectra in the A-dimensional space it is advisable to sample the time domain starting at the origin (Fig. 1). Thus, all APSY pulse sequences should allow sampling access to this time domain point with zero evolution time. 

In a set of j projections with different projection vectors pi/, an Y-dimensional cross peak Q is projected orthogonally to the locations Qf Here,/is an arbitrary numeration of the set of j projections / = 1,. .., / In the 2D coordinate system of projection/ the projected cross peak has the position vector Ql = [v 

The Al-dimensional cross peak Q is located in an (A — 2)-dimensional subspace, which is orthogonal to the projection plane at the point Q (Fig. 1). The peak subgroup of an A-dimensional chemical shift correlation Q is the set of projected 

Peak picking min Signal-to-noise threshold for peak picking 

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