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Clustering and Heterogeneous P1 Distributions in Diamond Govern DNP Mechanisms at 6.9 and 13.8 T

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Nitrogen substitutions (P1 centers) in diamonds were shown to provide significant 13 C hyperpolarization at room temperature and high fields, with the presence of P1 clusters hypothesized to be essential. We compare the 6.9 and 13.8 T 13 C dynamic nuclear polarization (DNP) and electron paramagnetic resonance spectra of two single-crystal diamonds: one with a high P1 concentration (∼20 ppm) and abundant P1 clusters, and another with a low P1 concentration (∼3.5 ppm) and no clusters. The first exhibits a 540 ± 180 nm 13 C NMR enhancement with broad and narrow DNP features, whereas the second displays only weak, sharp DNP peaks after prolonged irradiation. The dependence of 13 C polarization buildup rate on millimeter-wave frequency distinguishes solid-effect (SE) from cross-effect (CE), confirming P1 clusters are essential for efficient high-field DNP. Moreover, we show that in the high-P1-concentration diamond, the SE and CE polarize distinct pools of 13 C nuclei, demonstrating DNP’s ability to map the spatial distribution of diamond defects.

Source: The Journal of Physical Chemistry Letters

DOI: 10.1021/acs.jpclett.5c01809

Authors: Orit Nir-Arad, David H. Shlomi, Raj K. Chaklashiya, Nurit Manukovsky, Ilia Kaminker

Institutions: Tel Aviv University, Northwestern University, University of California, Santa Barbara

Language: English

Topic: Advanced NMR Techniques and Applications

Subfield: Spectroscopy

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funder: Israel Science Foundation