%0 Journal Article %J Journal of Magnetic Resonance Series A %D 1993 %T Pure-Absorption-Mode Lineshapes and Sensitivity in 2-Dimensional Dynamic-Angle Spinning Nmr %A Grandinetti, P. J. %A Baltisberger, J. H. %A Llor, A. %A Lee, Y. K. %A Werner, U. %A Eastman, M. A. %A Pines, A. %K nuclei %B Journal of Magnetic Resonance Series A %V 103 %P 72-81 %8 Jun 1 %@ 1064-1858 %G English %U ://WOS:A1993LJ62500010 %N 1 %M WOS:A1993LJ62500010 %! Pure-Absorption-Mode Lineshapes and Sensitivity in 2-Dimensional Dynamic-Angle Spinning Nmr %R Doi 10.1006/Jmra.1993.1132 %0 Journal Article %J Israel Journal of Chemistry %D 1992 %T Correlation of Isotropic and Anisotropic Chemical-Shifts in Solids by 2-Dimensional Variable-Angle-Spinning Nmr %A Frydman, L. %A Chingas, G. C. %A Lee, Y. K. %A Grandinetti, P. J. %A Eastman, M. A. %A Barrall, G. A. %A Pines, A. %K magic-angle %X

We describe a new solid-state nuclear magnetic resonance (NMR) technique for correlating anisotropic and isotropic chemical shifts in powdered samples. Two-dimensional (2D) NMR spectra are obtained by processing signals acquired in independent experiments for different angles between the sample spinning axis and the Zeeman magnetic field. This 2D NMR approach can therefore resolve individual static anisotropic lineshapes according to their isotropic chemical shift frequencies, without use of sudden mechanical motions or multiple-pulse irradiation schemes. Applications of the technique are illustrated with an analysis of the chemical shift anisotropy for the eight distinct C-13 sites in tyrosine.

%B Israel Journal of Chemistry %V 32 %P 161-164 %@ 0021-2148 %G English %U ://WOS:A1992KT51700005 %N 2-3 %M WOS:A1992KT51700005 %! Correlation of Isotropic and Anisotropic Chemical-Shifts in Solids by 2-Dimensional Variable-Angle-Spinning Nmr %0 Journal Article %J Journal of Magnetic Resonance %D 1992 %T Double-Tuned Hopping-Coil Probe for Dynamic-Angle-Spinning Nmr %A Eastman, M. A. %A Grandinetti, P. J. %A Lee, Y. K. %A Pines, A. %K axis %B Journal of Magnetic Resonance %V 98 %P 333-341 %8 Jun 15 %@ 0022-2364 %G English %U ://WOS:A1992HZ62300008 %N 2 %M WOS:A1992HZ62300008 %! Double-Tuned Hopping-Coil Probe for Dynamic-Angle-Spinning Nmr %R Doi 10.1016/0022-2364(92)90136-U %0 Journal Article %J Nature %D 1992 %T Quantification of the Disorder in Network-Modified Silicate-Glasses %A Farnan, I. %A Grandinetti, P. J. %A Baltisberger, J. H. %A Stebbins, J. F. %A Werner, U. %A Eastman, M. A. %A Pines, A. %K time %X

Local order in silicate glasses has been observed by many experimental techniques to be similar to that in crystalline materials. Details of the intermediate-range order are more elusive, but essential for understanding the lack of long-range symmetry in glasses and the effect of composition on glass structure. Two-dimensional O-17 dynamic-angle-spinning nuclear magnetic resonance experiments reveal intermediate-range order in the distribution of inter-tetrahedral (Si-O-Si) bond angles and a high degree of order in the disposition of oxygen atoms around the network-modifying cations.

%B Nature %V 358 %P 31-35 %8 Jul 2 %@ 0028-0836 %G English %U ://WOS:A1992JB34100043 %N 6381 %M WOS:A1992JB34100043 %! Quantification of the Disorder in Network-Modified Silicate-Glasses %R Doi 10.1038/358031a0 %0 Journal Article %J Journal of Chemical Physics %D 1992 %T Variable-Angle Correlation Spectroscopy in Solid-State Nuclear-Magnetic-Resonance %A Frydman, L. %A Chingas, G. C. %A Lee, Y. K. %A Grandinetti, P. J. %A Eastman, M. A. %A Barrall, G. A. %A Pines, A. %K axis %X

We describe here a new solid-state nuclear-magnetic-resonance (NMR) experiment for correlating anisotropic and isotropic chemical shifts of inequivalent nuclei in powdered samples. Spectra are obtained by processing signals arising from a spinning sample, acquired in independent experiments as a function of the angle between the axis of macroscopic rotation and the external magnetic field. This is in contrast to previously proposed techniques, which were based on sudden mechanical flippings or multiple-pulse sequences. We show that the time evolution of variable-angle-spinning signals is determined by a distribution relating the isotropic frequencies of the spins with their corresponding chemical shift anisotropies. Fourier transformation of these data therefore affords a two-dimensional NMR spectrum, in which line shapes of isotropic and anisotropic interactions are correlated. Theoretical and experimental considerations involved in the extraction of this spectral information are discussed, and the technique is illustrated by an analysis of C-13 NMR anisotropy in glycine, cysteine, and p-anisic acid.

%B Journal of Chemical Physics %V 97 %P 4800-4808 %8 Oct 1 %@ 0021-9606 %G English %U ://WOS:A1992JR33800022 %N 7 %M WOS:A1992JR33800022 %! Variable-Angle Correlation Spectroscopy in Solid-State Nuclear-Magnetic-Resonance %R Doi 10.1063/1.463860