Broadband adiabatic inversion pulses for cross polarization in wideline solid-state NMR spectroscopy

Kristopher J. Harris, Adonis Lupulescu, Bryan E.G. Lucier, Lucio Frydman, Robert W. Schurko

Research output: Contribution to journalArticlepeer-review


Efficient acquisition of ultra-wideline solid-state NMR powder patterns is a continuing challenge. In particular, when the breadth of the powder pattern is much larger than the cross-polarization (CP) excitation bandwidth, transfer efficiencies suffer and experimental times are greatly increased. Presented herein is a CP pulse sequence with an excitation bandwidth that is up to ten times greater than that available from a conventional spin-locked CP pulse sequence. The pulse sequence, broadband adiabatic inversion CP (BRAIN-CP), makes use of the broad, uniformly large frequency profiles of chirped inversion pulses, to provide these same characteristics to the polarization transfer process. A detailed theoretical analysis is given, providing insight into the polarization transfer process involved in BRAIN-CP. Experiments on spin-1/2 nuclei including 119Sn, 199Hg and 195Pt nuclei are presented, and the large bandwidth improvements possible with BRAIN-CP are demonstrated. Furthermore, it is shown that BRAIN-CP can be combined with broadband frequency-swept versions of the Carr-Purcell-Meiboom-Gill experiment (for instance with WURST-CPMG, or WCPMG for brevity); the combined BRAIN-CP/WCPMG experiment then provides multiplicative signal enhancements of both CP and multiple-echo acquisition over a broad frequency region.

Original languageEnglish
Pages (from-to)38-47
Number of pages10
StatePublished - Nov 2012

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Nuclear and High Energy Physics
  • Biophysics
  • Biochemistry


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