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Updated: Jun 28, 2026

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
14N Polarization Inversion Spin Exchange at Magic Angle (PISEMA)
Chunqi Qian1, Riqiang Fu, Peter Gor'kov
1Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Tallahassee, FL 32310, USA.
Abstract:
Polarization Inversion Spin Exchange at Magic Angle (PISEMA) is a powerful experiment for determining peptide orientation in uniformly aligned samples such as planar membranes. In this paper, we present (14)N-PISEMA experiment which correlates (14)N quadrupolar coupling and (14)N-(1)H dipolar coupling. (14)N-PISEMA enables the use of (14)N quadrupolar coupling tensor as an ultra sensitive probe for peptide orientation and can be carried out without the need of isotope enrichment. The experiment is based on selective spin-exchange between a proton and a single-quantum transition of (14)N spins. The spin-exchange dynamics is described and the experiment is demonstrated with a natural abundant N-acetyl valine crystal sample.
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