Local dynamics in rotating solids can be investigated by measuring enhanced transverse relaxation rates near rotary resonance conditions. In contrast, this effect is not expected in rotating solutions, as first-order anisotropic interactions are averaged out. For rotating solutions, we show how enhanced transverse relaxation near rotary resonance reports on fluctuations that are introduced due to imperfect hardware, with rf-field imperfections being the primary source of the effect.

We have performed a low frequency EPR study on two solid-state batteries (NMC||Li-metal and NMC||Si-based) sealed inside an industrial and standard aluminum laminated pouch cell. EPR imaging allowed us to locate the metallic anode through the Al-based pouch cell confirming the good penetration of the microwave field through the pouch. We think our approach provides valuable insight for the battery community paving the way to the quality control of industrial and commercial batteries.

Quantification of heterogeneous systems such as unstructured or semi-structured (bio)macromolecules is an important but challenging task. Pulse EPR methods can contribute by characterizing the local nuclear environment of a spin centre. Here, we provide a detailed assessment of a pulse EPR technique derived from a RIDME experiment. We review the theoretical principles, discuss the data analysis and demonstrate an application to a spin-labeled macromolecule supported by in silico modelling.

The time evolution of a spin system in NMR can be represented in simple cases by an analytical equation, which is often better suited to promote physical understanding for teaching as well as for scientific discussion than numerical results. A method is presented that can be used to find analytical equations even for moderately complex problems. This is based on the fact that the coefficients of suitable commutator equation systems can be inserted directly into templates for propagation rules.

Electron spins sense their environment via magnetic interactions. An important contribution stems from nuclear spins in their vicinity. They cause loss of coherence and thus reduce resolution of spectra obtained by experiments on electron spins and the efficiency of transferring electron-spin magentization to other nuclear spins. Here we study how protons in trityl radicals contribute to coherence loss. Such coherence loss is slower in the presence of a strong microwave field.

Electron spin dynamics during microwave irradiation are of increasing interest in electron paramagnetic resonance (EPR) spectroscopy. Here, we show that these dynamics can be probed by modern pulse EPR experiments that use shaped microwave pulses. Combined with spin dynamics simulations, these results provide a starting point for optimizing existing EPR experiments and for developing new pulse sequences.

We believe that, in addition to nontrivial theoretical interest, the proposed work offers experimenters a reliable time interval in which the experimentally measured signal allows a relatively simple interpretation uncomplicated by contributions from three-particle dynamical correlations of having spins nuclei in condensed matter.

Sensitivity is often the limiting factor in ENDOR. Here, we demonstrate how using chirp radiofrequency pulses can improve ENDOR sensitivity up to 3-9-fold, with the strongest increase for broader lines often encountered in disordered solids for nuclei such as nitrogen and metals. The resulting drastic speed-up in acquisition times renders also 2D ENDOR more feasible, as we demonstrate in 2D TRIPLE showing correlations of Cu hyperfine couplings.