Improving SABRE hyperpolarization with highly nonintuitive pulse sequences: Moving beyond avoided crossings to describe dynamics.

Journal Article (Journal Article)

Signal amplification by reversible exchange (SABRE) creates "hyperpolarization" (large spin magnetization) using a transition metal catalyst and parahydrogen, addressing the sensitivity limitations of magnetic resonance. SABRE and its heteronuclear variant X-SABRE are simple, fast, and general, but to date have not produced polarization levels as large as more established methods. We show here that the commonly used theoretical framework for these applications, which focuses on avoided crossings (also called level anticrossings or LACs), steer current SABRE and X-SABRE experiments away from optimal solutions. Accurate simulations show astonishingly rich and unexpected dynamics in SABRE/X-SABRE, which we explain with a combination of perturbation theory and average Hamiltonian approaches. This theoretical picture predicts simple pulse sequences with field values far from LACs (both instantaneously and on average) using different terms in the effective Hamiltonian to strategically control evolution and improve polarization transfer. Substantial signal enhancements under such highly nonintuitive conditions are verified experimentally.

Full Text

Duke Authors

Cited Authors

  • Eriksson, SL; Lindale, JR; Li, X; Warren, WS

Published Date

  • March 2022

Published In

Volume / Issue

  • 8 / 11

Start / End Page

  • eabl3708 -

PubMed ID

  • 35294248

Pubmed Central ID

  • PMC8926330

Electronic International Standard Serial Number (EISSN)

  • 2375-2548

International Standard Serial Number (ISSN)

  • 2375-2548

Digital Object Identifier (DOI)

  • 10.1126/sciadv.abl3708

Language

  • eng