title: Measurement of spin-lattice relaxation times of 13C in organic solids.
abstract: A transient nuclear Overhauser effect (NOE) makes measurements of the 13C spin-lattice relaxation times in organic solids complicated. Extended Solomon equations are applied in order to describe 13C spin-lattice relaxation with 1H r.f. field irradiation. Spin-lattice relaxation under r.f. irradiation is shown to be generally a triple-exponential process, but it can be reduced to be single-exponential under stronger r.f. field irradiation as well as in the absence of 1H initial magnetizations. Based on numerical calculations, the difference between spin-lattice relaxation curves obeying T1C < T1H and those obeying T1C > T1H is clearly indicated. The methyl group resonances in solid-state L-valine are examined, and the experimental results agree well with the theoretical results.
authors.affiliation: Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics, Chinese Academy of Sciences, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Zhou
authors.forename: R
authors.initials: R
authors.lastname: Fu
authors.forename: J Z
authors.initials: JZ
authors.lastname: Hu
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Ye
mesh_terms: D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy
chemical_list: D002247:Carbon Isotopes