J.-N. Dumez, P. Håkansson, S. Mamone, B. Meier, G. Stevanato, J. T. Hill-Cousins, S. S. Roy, R. C. D. Brown, G. Pileio and M. H. Levitt, “Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation,” J. Chem. Phys. 142, 044506 (2015).
http://dx.doi.org/10.1063/1.4906273An executable SpinDynamica notebook is here:
http://www.spindynamica.soton.ac.uk/files/2015/01/methylLLS_v4.nb_.zip