Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 1, 1999 | public
Journal Article

Quantum Statistical Corrections to Dynamic Nuclear Magnetic Resonance


A quantum statistical treatment of the chemical exchange between molecular eigenstates or conformations revealed previously unsuspected dynamic terms in the spin Hamiltonian operator that describes fast exchange. These terms resulted from the effect of nuclear spin on rotational and vibrational relaxation. With the traditional theory, an interpretation of new carbon-13 nuclear magnetic resonance measurements of the chemical shift of methylcyclohexane in solution showed fast-exchange equilibrium constants that were inconsistent with the slow-exchange free-energy difference and were spread over a range of 30 percent for the various carbon-13 positions. Modeling of the new terms indicated that they have the correct magnitude and temperature dependence to reconcile these inconsistencies.

Additional Information

© 1999 American Association for the Advancement of Science. Received 30 April 1998; accepted 16 November 1998. This work was supported by NSF (grant CHE-9005964). L.J.M. acknowledges an NSF Graduate Fellowship and a Department of Defense National Defense Science and Engineering Graduate Fellowship.

Additional details

August 19, 2023
October 18, 2023