Filter diagonalization method for processing PFG NMR data.

Obtaining diffusion coefficients from PFG NMR diffusion (a.k.a DOSY) data is, in the general case, an ill-posed problem. Numerous methods for processing such data have therefore been developed, each with different constraints and assumptions. The Regularized Resolvent Transform (RRT) is a proven and robust method for spectral inversion. In earlier papers RRT, albeit very slow, was argued to be superior for DOSY processing to a related algorithm, the Filter Diagonalization Method (FDM). Here FDM is revisited and a new regularization method is implemented, which drastically improves the performance and provides spectra of comparable or better quality to those provided by RRT. Both the RRT and the FDM for DOSY processing have been implemented as options in the free and open source DOSY Toolbox.