QUADRELAX: A Program for Computing Relaxation Data for Quadrupolar Nuclei, Including Chemical Exchange Effects

Based on Redfield's theory of nuclear magnetic relaxation, a computer package capable of computing longitudinal and transverse relaxation rates and amplitudes as well as dynamic frequency shift for all quadrupolar nuclei (all integer spin numbers from 1 to 6 and all half-integer spin numbers from <mml:mfrac>32</mml:mfrac> to <mml:mfrac>92</mml:mfrac>) in all molecular movement regimes including the effects of two-site chemical exchange was introduced. As an example, the calculated longitudinal and transverse relaxation rates for spin <mml:mfrac>92</mml:mfrac> nuclei were plotted versus 0c which had not been reported previously. These diagrams show the possibility of the usage of the central transition (mI=-<mml:mfrac>12</mml:mfrac><mml:mfrac>12</mml:mfrac>) in the NMR of biomolecules containing spin <mml:mfrac>92</mml:mfrac> nuclei. The data produced by this package can be used for simulating the NMR spectra of quadrupolar nuclei, involving in exchange processes, which can be used to extract kinetic data from NMR spectra. The accuracy of this package was confirmed using it for reproducing of the data in some problems investigated earlier. Our data are in full accordance with the conducted research in this area. (c) 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part A 43A: 228-236, 2015.