EPR Everywhere

Abstract

This review is inspired by the contributions from the University of Denver group to low-field EPR, in honor of Professor Gareth Eaton's 80th birthday. The goal is to capture the spirit of innovation behind the body of work, especially as it pertains to development of new EPR techniques. The spirit of the DU EPR laboratory is one that never sought to limit what an EPR experiment could be, or how it could be applied. The most well-known example of this is the development and recent commercialization of rapid-scan EPR. Both of the Eatons have made it a point to remain knowledgeable on the newest developments in electronics and instrument design. To that end, our review touches on the use of miniaturized electronics and applications of single-board spectrometers based on software-defined radio (SDR) implementations and single-chip voltage-controlled oscillator (VCO) arrays. We also highlight several non-traditional approaches to the EPR experiment such as an EPR spectrometer with a "wand" form factor for analysis of the OxyChip, the EPR-MOUSE which enables non-destructive in situ analysis of many non-conforming samples, and interferometric EPR and frequency swept EPR as alternatives to classical high Q resonant structures.

Quantifying Crude Oil Contamination in Sand and Soil by EPR Spectroscopy

“…Recently, small and mobile EPR scanners have indeed been suggested that combine portability with the superior detection sensitivity that is known from lab-based EPR instruments as a consequence of the larger electron magnetic moment [13,14]. See [15] for an overview of recent low-field and portable EPR applications.…”

Sample Holders for Sub-THz Electron Spin Resonance Spectroscopy

“…S INCE the discovery of Electron Spin Resonance (ESR) by Zavoisky in 1944 at Kazan University [1], there has been vast development in the field of magnetic resonance. Nowadays, ESR methodologies cover various science disciplines [2], including solid-state physics [3]- [7], quantum information processing [8], [9], biophysics [10]- [14], and chemistry [15]- [17].…”

“…ESR has broad applications ranging from physics, over chemistry to biology, and therefore a wide variety of samples types exist with different requirements [2], [48]. The message of this article is to show that any spectrometer using a sample holder without a resonator (non-resonant sample holder) has a wide range of applications, which can be reached by designing new sample holders.…”

Hyperpolarized 29Si magnetic resonance spectroscopy of selectively radical-embedded silica nanoparticles

“…The results can be explained by the EPR signal arises from the electron Zeeman interaction and the hyperfine interaction then causes the splitting into an equal intensity triplet; however, hyperfine anisotropy may contribute to the dominant effect for observing line shape of organic radical at X-band frequencies in the solid state. 22 In particular, the electron Zeeman interaction (H EZ ) is occurred between the unpaired electron and the magnetic field. 23 While the electron-nuclear hyperfine interaction (H HF ) is between unpaired electron ( S = 1/2) and 14 N nucleus ( I = 1) of the nitroxide group (N–O˙).…”