RIDME Spectroscopy: New Topics Beyond the Determination of Electron Spin–Spin Distances

Relaxation-induced dipolar modulation enhancement (RIDME) is a pulse EPR experiment originally designed to determine distances between spin labels. However, RIDME has several features that make it an efficient tool in a number of “nonconventional” applications, away from the original purpose of this pulse experiment. RIDME appears to be an interesting experiment to probe longitudinal electron spin dynamics, e.g., in relation to qubits research, to probe distributions of exchange couplings, useful for the design of molecular magnets, and to determine important details of electron spin interactions with the nuclear spin bath, which is related to the dynamic nuclear polarization and soft materials research. We also anticipate interesting applications of RIDME in the structural biology of biopolymers as well as their interactions, aggregation, and phase separation. It is not excluded that in the near future such “nonconventional” topics could grow in number and evolve into the main application area of RIDME.