Heteronuclear dipolar recoupling in solid-state nuclear magnetic resonance by amplitude-, phase-, and frequency-modulated Lee-Goldburg cross-polarization
2005 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 122, no 4Article in journal (Refereed) Published
This paper presents a theoretical, numerical, and experimental study of phase- and frequency-switched Lee-Goldburg cross-polarization (FSLG-CP) under magic-angle spinning conditions. It is shown that a well-defined amplitude modulation of one of the two radio-frequency (rf) fields in the FSLG-CP sequence results in highly efficient heteronuclear dipolar recoupling. The recoupled dipolar interaction is gamma-encoded and, under ideal conditions, the effective spin Hamiltonian is equivalent to that in continuous-wave Lee-Goldburg CP. In practice, however, FSLG-CP is less susceptible to rf field mismatch and inhomogeneity, and provides better suppression of H-1 spin diffusion. The performance of FSLG-CP is experimentally demonstrated on liquid-crystalline samples exhibiting motionally averaged dipolar couplings.
Place, publisher, year, edition, pages
2005. Vol. 122, no 4
angle-spinning nmr, magic-angle, liquid-crystals, rotating solids, mas nmr, hexaoctyloxy-rufigallol, coherence transfer, rotary resonance, pulse sequences, columnar phases
IdentifiersURN: urn:nbn:se:kth:diva-14506DOI: 10.1063/1.1834569ISI: 000226807000047OAI: oai:DiVA.org:kth-14506DiVA: diva2:332547
QC 201005252010-08-052010-08-05Bibliographically approved