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Use tract.dl as the original sequence reference. Calibrate the pulses, gradients, carrier, and water suppression for your instrument and sample. The file documents p1, p5, p11, sp1, sp2, and the relaxation-delay increment. Compatibility with a particular TopSpin release must be checked on the instrument.

The legacy split_all_int.pl script reads ./ser and writes ./ser1 and ./ser2 with its supplied settings. It assumes 4-byte data points, 1,024 direct-dimension points, and 20 delay points. Edit initnr, endnr, tdpoints, and directtdpoints to match the acquisition. Run it only on a working copy in a folder without existing output files; it overwrites files with those names.

Process the separated decay series and determine the α- and β-spin-state relaxation rates. The splitter itself does not fit relaxation data.

Open tract.xls in a compatible spreadsheet application. Review the field and physical constants, and replace the example relaxation rates with measured values. The supplied sheet contains a 750 MHz example, Rβ = 64 s⁻¹ and Rα = 13 s⁻¹.

The worksheet presents a cubic equation in τc; select the physically meaningful positive root and check units. Its stored result is an example, not an automatic browser calculation or a result for your sample.

TRACT uses the difference between spin-state relaxation rates to estimate an effective rotational correlation time. It is useful for assessing sample behavior and planning NMR experiments. Internal motion, anisotropic tumbling, and experimental conditions affect interpretation; τc should not be treated as a direct molecular-weight measurement.