Towards chemical structure resolution with nanoscale nuclear magnetic resonance spectroscopy

TL;DR

This paper demonstrates a significant enhancement in nanoscale NMR spectral resolution using shallow NV sensors, enabling detailed chemical structure analysis at the molecular level.

Contribution

It introduces a correlation spectroscopy method with NV diamond sensors that greatly improves spectral resolution for chemical structure determination.

Findings

Over two orders of magnitude spectral resolution improvement

Ability to observe chemical shifts in ~1 T magnetic fields

Surface molecular diffusion limits current resolution

Abstract

Nuclear magnetic resonance (NMR) spectroscopy has approached the limit of single molecule sensitivity, however the spectral resolution is currently insufficient to obtain detailed information on chemical structure and molecular interactions. Here we demonstrate more than two orders of magnitude improvement in spectral resolution by performing correlation spectroscopy with shallow nitrogen-vacancy (NV) magnetic sensors in diamond. In principle, the resolution is sufficient to observe chemical shifts in $\sim$1 T magnetic fields, and is currently limited by molecular diffusion at the surface. We measure oil diffusion rates of $D = 0.15 - 0.2$\,nm$^2/\mathrm{\mu}$s within (5 nm)$^3$ volumes at the diamond surface.