muT2-NMR: Micro-Scale Correlation Relaxometry for in-situ High-Pressure Nuclear Magnetic Resonance

TL;DR

This paper introduces muT2-NMR, a novel time-domain relaxometry method for high-pressure NMR in diamond anvil cells, enabling resolution of molecular subunits despite spectral overlap at pressures up to 72 GPa.

Contribution

The work presents muT2-NMR, a new relaxometry framework tailored for high-pressure NMR, improving resolution of molecular subunits under extreme conditions.

Findings

Successfully applied to hydrogen-rich solids up to 72 GPa

Resolved individual molecular subunits in relaxation space

Demonstrated experimental robustness and flexibility

Abstract

Over the last decade, frequency-domain in-situ high-pressure nuclear magnetic resonance (NMR) spectroscopy in diamond anvil cells (DACs) has been employed as a structural and electronic probe of condensed matter systems at pressures well into the megabar range. However, extensive spin interactions and sample heterogeneities under pressure often lead to significant spectral overlap, inhibiting independent observation of chemically similar spin sub-species in the same sample. In this work, we introduce a time-domain relaxometry framework specifically suited for DAC experiments, named muT2-NMR. Experimental flexibility and operational robustness are benchmarked on three hydrogen-rich molecular solids at pressures up to 72 GPa. We demonstrate that muT2-NMR can resolve individual molecular subunits in relaxation space, paving the way for novel high-pressure, high-resolution NMR applications in molecular solids.