Truncated Cross Effect Dynamic Nuclear Polarization: An Overhauser Effect Doppelgänger

Asif Equbal, Yuanxin Li, Alisa Leavesley, Shengdian Huang, Suchada Rajca, Andrzej Rajca, Songi Han

Research output: Contribution to journalArticlepeer-review


The discovery of a truncated cross-effect (CE) in dynamic nuclear polarization (DNP) NMR that has the features of an Overhauser-effect DNP (OE-DNP) is reported here. The apparent OE-DNP, where minimal μw power achieved optimum enhancement, was observed when doping Trityl-OX063 with a pyrroline nitroxide radical that possesses electron-withdrawing tetracarboxylate substituents (tetracarboxylate-ester-pyrroline or TCP) in vitrified water/glycerol at 6.9 T and at 3.3 to 85 K, in apparent contradiction to expectations. While the observations are fully consistent with OE-DNP, we discover that a truncated cross-effect (tCE) is the underlying mechanism, owing to TCP's shortened T1e. We take this observation as a guideline and demonstrate that a crossover from CE to tCE can be replicated by simulating the CE of a narrow-line (Trityl-OX063) and a broad-line (TCP) radical pair, with a significantly shortened T1e of the broad-line radical.

Original languageEnglish (US)
Pages (from-to)2175-2180
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number9
StatePublished - May 3 2018

ASJC Scopus subject areas

  • General Materials Science
  • Physical and Theoretical Chemistry


Dive into the research topics of 'Truncated Cross Effect Dynamic Nuclear Polarization: An Overhauser Effect Doppelgänger'. Together they form a unique fingerprint.

Cite this