Abstract
Symmetry plays an important role in the retention or annihilation of a desired interaction Hamiltonian in NMR experiments. Here, we explore the role of symmetry in the radio-frequency interaction frame Hamiltonian of the refocused-continuous-wave (rCW) pulse scheme that leads to efficient H-1 heteronuclear decoupling in solid-state NMR. It is demonstrated that anti-periodic symmetry of single-spin operators (I-x, I-y, I-z) in the interaction frame can lead to complete annihilation of the H-1-H-1 homonuclear dipolar coupling effects that induce line broadening in solid-state NMR experiments. This symmetry also plays a critical role in cancelling or minimizing the effect of H-1 chemical-shift anisotropy in the effective Hamiltonian. An analytical description based on Floquet theory is presented here along with experimental evidences to understand the decoupling efficiency of supercycled (concatenated) rCW scheme.
Original language | English |
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Article number | 104202 |
Number of pages | 9 |
Journal | J. Chem. Phys. |
Volume | 146 |
Issue number | 10 |
DOIs | |
State | Published - 14 Mar 2017 |