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Cross‐polarization dynamics and proton dipolar local field measurements in some organic compounds
Author(s) -
Reinheimer Pierre,
Hirschinger Jérôme,
Gilard Patrick,
Goetz Noël
Publication year - 1997
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/(sici)1097-458x(199711)35:11<757::aid-omr168>3.0.co;2-d
Subject(s) - chemistry , dipole , polarization (electrochemistry) , local field , magic angle spinning , spin diffusion , molecular physics , magic angle , exponential function , molecular dynamics , chemical physics , atomic physics , nuclear magnetic resonance , computational chemistry , nuclear magnetic resonance spectroscopy , condensed matter physics , thermodynamics , diffusion , physics , stereochemistry , mathematical analysis , mathematics , organic chemistry
Hartmann–Hahn inversion–recovery cross‐polarization magic‐angle spinning experiments were performed for all types of protonated carbons (CH n with n =1, 2 and 3). The resulting non‐exponential decays were analyzed using both a simple memory function approach and density matrix calculations. Although the memory function approach provides a useful analytical description of the cross‐polarization dynamics, the density matrix method is required to account better for the details of the spin dynamics. 13 C‐detected dipolar local fields of protons were measured using the wideline separation experiment. It was observed that the resulting local free induction decays may be quantitatively described by their local second moment. Moreover, the local spin diffusion process controlling the second stage of the cross‐polarization dynamics is directly related to the strength of the local dipolar field of protons. © 1997 John Wiley & Sons, Ltd.