[8a-N303-1~8] 10.5 Application of magnetic field

9:00 AM - 9:15 AM JST(12:00 AM - 12:15 AM UTC)

[8a-N303-1] Spectral analysis of solid-state oxygen-17 NMR spectra of hexagonal ice

〇Kazuhiko Yamada¹ (1.Nihon Univ.)

Keywords:

Solid-state oxygen-17 NMR,Ice

Experimental and theoretical investigations of line shapes in solid-state ¹⁷O NMR spectra of hexagonal ice, I_h, have been presented. Stationary ¹⁷O NMR spectra of ice I_h at temperatures from 143 to 280 K are obtained at 11.7 and 16.4 T. Line shapes drastically change as temperatures increase from 143 and 243 K; at 253 K and above, pseudo-isotropic line shapes appear, indicating the presence of re-orientational motions. The Ratcliffe’s model, which involves twelve orientations and four-step jumps for water re-orientational motions, is applied for analyzing the NMR spectra at temperatures below 243 K. At 253 K and above, it is found that the isotropic line shapes arise from proton disorder with respect to the solid-state ¹⁷O NMR time scale, producing pseudo-icosahedral motional averaging that can completely average out second-order quadrupole interactions.