Theoretical studies of the spin dynamics of quadrupolar nuclei at rotational resonance conditions
نویسندگان
چکیده
A theory of the spin dynamics of I53/2 quadrupolar nuclei in the sudden-passage limit is discussed in relation to the recently observed rotational resonance ~RR! effects on the excitation and conversion of triple-quantum coherence in the FASTER multiple-quantum magic-angle spinning ~MQMAS! experiments @T. Vosegaard, P. Florian, D. Massiot, and P. J. Grandinetti, J. Chem. Phys. 114, 4618 ~2001!#. A novel interaction frame, which combines the quadrupolar interaction with the central transition radio frequency irradiation, is shown to be useful in understanding the complex spin dynamics at and away from RR conditions. Analytical expressions for the Hamiltonian obtained from bimodal Floquet theory are included in order to provide insight into the spin dynamics observed in the FASTER MQMAS experiments. Numerical simulations have been performed and were found to support the theoretical formalism. © 2002 American Institute of Physics. @DOI: 10.1063/1.1421613#
منابع مشابه
Residual dipolar coupling between quadrupolar nuclei under magic-angle spinning and double-rotation conditions.
Residual dipolar couplings between spin-1/2 and quadrupolar nuclei are often observed and exploited in the magic-angle spinning (MAS) NMR spectra of spin-1/2 nuclei. These orientation-dependent splittings contain information on the dipolar interaction, which can be translated into structural information. The same type of splittings may also be observed for pairs of quadrupolar nuclei, although ...
متن کاملResidual dipolar couplings between quadrupolar nuclei in high resolution solid state NMR: Description and observations in the high-field limit
Nonsecular dipolar couplings between spin2 nuclei that are in close proximity to quadrupolar spins have been extensively documented in solid state nuclear magnetic resonance ~NMR!, particularly when involving directly bonded S5C, I5N spin pairs. These couplings arise due to the quadrupole-induced tilting of I’s nuclear spin quantization axes, and their most notable characteristic is that they c...
متن کاملTheoretical investigations of IÄ5Õ2 quadrupolar spin dynamics in the sudden-passage regime
The theoretical approach utilizing bimodal Floquet theory in the quadrupolar/central-transition interaction frame, presented in an earlier article @J. D. Walls, K. H. Lim, and A. Pines, J. Chem. Phys. 116, 79 ~2002!#, is extended to describe the more complicated spin dynamics of I55/2 spin systems. Rotary resonance effects occur when the strength of the radio-frequency irradiation, v1 , matches...
متن کاملMolecular dynamics of half-integer quadrupolar nuclei studied by QCPMG solid-state NMR experiments on static and rotating samples. Theory and simulations.
Simulations of QCPMG NMR type experiments have been used to explore dynamic processes of half-integer quadrupolar nuclei in solids. By setting up a theoretical approach that is well suited for efficient numerical simulations the QCPMG type experiments have been analyzed regarding the effect of the magnitude of the EFG- and CSA-tensors, the spin-quantum number, different dynamical processes and ...
متن کامل2D Off-Resonance Nutation NQR Spectroscopy of Spin 3/2 Nuclei*
The effects of off-resonance irradiation in nutation NQR experiments are demonstrated both experimentally and theoretically. The theoretical description of the off-resonance effects in 2D nutation NQR spectroscopy is given, and general exact formulas for the asymmetry parameter are obtained. It is shown that the outcome of the off-resonance nutation experiments depends on the data acquisition p...
متن کامل