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Updated: Feb 5, 2026

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy
Published on: April 13, 2022
Breakdown of Carr-Purcell Meiboom-Gill spin echoes in inhomogeneous fields
Nanette N Jarenwattananon1, Louis-S Bouchard1
1Department of Chemistry and Biochemistry, University of California Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1059, USA.
Abstract:
The Carr-Purcell Meiboom-Gill (CPMG) experiment has been used for decades to measure nuclear-spin transverse (T2) relaxation times. In the presence of magnetic field inhomogeneities, the limit of short interpulse spacings yields the intrinsic T2 time. Here, we show that the signal decay in such experiments exhibits fundamentally different behaviors between liquids and gases. In gases, the CPMG unexpectedly fails to eliminate the inhomogeneous broadening due to the non-Fickian nature of the motional averaging.
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