Line shapes in CP/MAS (13)C NMR spectra of cellulose I.
The CP/MAS (13)C NMR line shape of cellulose I has been qualitatively analyzed by direct simulations using the Ornstein-Uhlenbeck stochastic process and the Kubo model. Both approaches describe a anhydroglucose C4 carbon as a oscillator with fluctuating Larmor frequency. The NMR resonance frequency is written omega=omega +omega(t), where the fluctuating part with zero mean was modelled as a stationary Markov diffusion process. The simulation results both motivates the use of multiple line shapes when fitting CP/MAS (13)C NMR spectra recorded on cellulose I and gives some insights into why signals from crystalline cellulose I give rise to Lorentzian line shapes.
Larsson
Per Tomas
PT
STFI-Packforsk AB, SE-114 86 Stockholm, Sweden. tomas.larsson@stfi.se
Westlund
Per-Olof
PO
D002236:Carbohydrate Conformation; D002482:Cellulose / Q000737:chemistry*; D003461:Crystallography; D003368:Gossypium / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008962:Models, Theoretical
D002482:Cellulose