Theory of single-molecule NMR detected by real-time ESR
Phys. Rev. B 114, 065430 – Published 29 July, 2026
DOI: https://doi.org/10.1103/3ql7-plp4
Abstract
In relation to recent experimental data [Y. Manassen et al., J. Magn. Reson. 374, 107863 (2025)], we develop a theory framework for demonstrating the feasibility of detecting sharp Nuclear Magnetic Resonance (NMR) oscillations in a real-time ESR data. The procedure is to follow real-time oscillations of the ESR signal measured at a selected frequency of a hyperfine transition. We study a variety of systems such as a single radical molecule with one or two hyperfine coupled nuclei or two molecules that coexist as either radicals or nonradicals, facilitated by charge transfer. We develop a master equation for describing these scenarios and find parameters for which a sharp NMR line can be observed. We show that in all cases an off-diagonal term in the hyperfine tensor is essential for the observation.
