Field-swept S-33 NMR spectra of a cyclic octaatomic molecule of elemental sulfur, alpha-S-8, are presented. The spectra were acquired at a Larmor frequency of 16.2 MHz and using a superconducting magnet at between 6.32 and 0.50 T. Methods were developed for analyzing the field-swept S-33 NMR spectra in which both Zeeman and quadrupole interactions were dominant. The quadrupole coupling constant, C-Q, and the asymmetry parameter, eta(Q), for alpha-S-8 were found to be 43.68 MHz and 0.57, respectively. T-1 measurements of alpha-S-8 were conducted using the nuclear quadrupole resonance signals, and the activation energy was determined to be 54(1) kJ mol(-1) from these T-1 measurements. The molecular motion was assigned to ring-puckering of alpha-S-8 molecules within the crystal structure. (C) 2014 Elsevier B.V. All rights reserved.