Efficient orientational averaging by the extension of Lebedev grids via regularized octahedral symmetry expansion
2006 (English)In: Journal of magnetic resonance (San Diego, Calif. 1997: Print), ISSN 1090-7807, Vol. 181, no 1, 162-176 p.Article in journal (Refereed) Published
Gaussian spherical quadrature methods in the guise of the Lebedev sampling grids are highly efficient for some orientational (“powder”) averaging problems in solid state NMR. However, their applicability is currently restricted, as the sets of orientations are derived analytically and because they are not well adapted to simulate the broad peakshapes encountered, for example, in the NMR on static powders or on half-integer quadrupolar spins subject to second order quadrupolar interactions under magic-angle spinning conditions. We remedy these problems by (i) introducing the recursive procedure regularized octahedral symmetry expansion (ROSE), to which any existing Lebedev set may be subjected. Each recursive step gives a 9-fold enlarged set of orientations. (ii) We demonstrate that ROSE-expanded grids, in conjunction with spectral interpolation, is well suited for calculating broad peakshapes. These advances combine into the apparently most efficient general-purpose two-angle orientational averaging technique proposed to date for solid state NMR applications.
Place, publisher, year, edition, pages
Elsevier , 2006. Vol. 181, no 1, 162-176 p.
Magic-angle-spinning NMR, Powder average, Regularization, Orientational symmetry, Gaussian spherical quadrature, Quadrupolar spins, Interpolation, Numerical integration
Research subject Physical Chemistry
IdentifiersURN: urn:nbn:se:su:diva-10649DOI: 10.1016/j.jmr.2006.04.008OAI: oai:DiVA.org:su-10649DiVA: diva2:177168