Abstract

Abstract Proton spin lattice relaxation rates have been measured at 15 and 30 MHz and down to 5 K for the partially deuterated molecular crystals 4-F-toluene, 4-Cl-toluene, and 2,6-Cl2-toluene. The behaviour of these materials is governed by methyl group tunnelling. As compared with the undeuterated compounds, the low temperature relaxation is enhanced and the details depend on the removal of the symmetry coupling between rotator and spin states. The hindering barriers remain unchanged, the A to E conversion rates are faster, and relaxation is dominated by spectral density contributions J(2ωo) and J(2ω0). In one case an additional influence of level-crossing energy transfer on relaxation is observed. Field-cycling spectroscopy reveals steps rather than peaks if the proton spin Zeeman and tunnelling splittings match

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.