Issue 8, 2015

Long-lived nuclear spin states far from magnetic equivalence


Clusters of coupled nuclear spins may form long-lived nuclear spin states, which interact weakly with the environment, compared to ordinary nuclear magnetization. All experimental demonstrations of long-lived states have so far involved spin systems which are close to the condition of magnetic equivalence, in which the network of spin–spin couplings is conserved under all pair exchanges of symmetry-related nuclei. We show that the four-spin system of trans-[2,3-13C2]-but-2-enedioate exhibits a long-lived nuclear spin state, even though this spin system is very far from magnetic equivalence. The 4-spin long-lived state is accessed by slightly asymmetric chemical substitutions of the centrosymmetric molecular core. The long-lived state is a consequence of the locally centrosymmetric molecular geometry for the trans isomer, and is absent for the cis isomer. A general group theoretical description of long-lived states is presented. It is shown that the symmetries of coherent and incoherent interactions are both important for the existence of long-lived states.

Graphical abstract: Long-lived nuclear spin states far from magnetic equivalence

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Article information

Article type
06 Dec 2014
23 Jan 2015
First published
23 Jan 2015
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2015,17, 5913-5922

Author version available

Long-lived nuclear spin states far from magnetic equivalence

G. Stevanato, S. Singha Roy, J. Hill-Cousins, I. Kuprov, L. J. Brown, R. C. D. Brown, G. Pileio and M. H. Levitt, Phys. Chem. Chem. Phys., 2015, 17, 5913 DOI: 10.1039/C4CP05704J

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