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Frequency-Swept Integrated Solid Effect |
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| Authors: | Thach V. Can Ralph T. Weber Joseph J. Walish Timothy M. Swager Robert G. Griffin |
| Affiliation: | 1. Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139 USA Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139 USA;2. Bruker BioSpin Corporation, Billerica, MA, 01821 USA;3. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139 USA;4. Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139 USA |
| Abstract: | The efficiency of continuous wave dynamic nuclear polarization (DNP) experiments decreases at the high magnetic fields used in contemporary high-resolution NMR applications. To recover the expected signal enhancements from DNP, we explored time domain experiments such as NOVEL which matches the electron Rabi frequency to the nuclear Larmor frequency to mediate polarization transfer. However, satisfying this matching condition at high frequencies is technically demanding. As an alternative we report here frequency-swept integrated solid effect (FS-ISE) experiments that allow low power sweeps of the exciting microwave frequencies to constructively integrate the negative and positive polarizations of the solid effect, thereby producing a polarization efficiency comparable to (±10 % difference) NOVEL. Finally, the microwave frequency modulation results in field profiles that exhibit new features that we coin the “stretched” solid effect. |
| Keywords: | dynamic nuclear polarization nuclear magnetic resonance integrated solid effect |