A comparison among different inversion methods for multi-exponential NMR relaxation data.

The inversion of data to be represented by sums or continuous distributions of exponentials is done by different algorithms and compared. The published CONTIN program presents a chosen solution with an appropriate amount of detail. An in-house program EXDISTR allows operative choice of various constraints in order to show the consequences in quality of fit of allowing various features such as extra maxima or minima. Another in-house program based on the system theory approach, IDENT, treats the data as the output samples of a linear, time-invariant, autonomous dynamic system.