An analysis of phase-modulated heteronuclear dipolar decoupling sequences in solid-state nuclear magnetic resonance.
The design of variants of the swept-frequency two-pulse phase modulation sequence for heteronuclear dipolar decoupling in solid-state NMR is reported, their performance evaluated, and compared with other established sequences like TPPM and SPINAL. Simulations performed to probe the role of the homonuclear (1)H-(1)H bath show that the robustness of the decoupling schemes improves with the size of the bath. In addition, these simulations reveal that the homonuclear (1)H-(1)H bath also leads to broad baselines at high MAS rates. Results from a study of the SPINAL decoupling scheme indicate that optimisation of the starting phase and phase increment improves its performance and efficiency at high MAS rates. Additionally, experiments performed on a liquid crystal display the role of the initial phase in SPINAL-64 and sequences in the SW(f)-TPPM family.
Thakur
Rajendra Singh
RS
Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India.
Kurur
Narayanan D
ND
Madhu
P K
PK
D002247:Carbon Isotopes; D005998:Glycine / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*
D002247:Carbon Isotopes; D005998:Glycine