Ultra-broadband EPR spectroscopy in field and frequency domains

2018 ◽  
Vol 20 (22) ◽  
pp. 15528-15534 ◽  
Author(s):  
P. Neugebauer ◽  
D. Bloos ◽  
R. Marx ◽  
P. Lutz ◽  
M. Kern ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Properties ◽  
Epr Spectroscopy ◽  
Paramagnetic Resonance ◽  
Powerful Technique ◽  
Electronic And Magnetic Properties ◽  
Wide Range ◽  
Frequency Domains ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) is a powerful technique to investigate the electronic and magnetic properties of a wide range of materials.

scholarly journals Monitoring of the Mechanism of Mn Ions Incorporation into Quantum Dots by Optical and EPR Spectroscopy

Photonics ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 107
Author(s):  
Yuriy G. Galyametdinov ◽  
Dmitriy O. Sagdeev ◽  
Andrey A. Sukhanov ◽  
Violeta K. Voronkova ◽  
Radik R. Shamilov
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Properties ◽  
Luminescent Properties ◽  
Manganese Concentration ◽  
Manganese Ions ◽  
Paramagnetic Resonance ◽  
Synthesis Of Nanoparticles ◽  
Zinc Sulfide Nanoparticles ◽  
Optical And Magnetic Properties ◽  
Electron Paramagnetic

Synthesis of nanoparticles doped with various ions can significantly expand their functionality. The conditions of synthesis exert significant influence on the distribution nature of doped ions and therefore the physicochemical properties of nanoparticles. In this paper, a correlation between the conditions of synthesis of manganese-containing cadmium sulfide or zinc sulfide nanoparticles and their optical and magnetic properties is analyzed. Electron paramagnetic resonance was used to study the distribution of manganese ions in nanoparticles and the intensity of interaction between them depending on the conditions of synthesis of nanoparticles, the concentration of manganese, and the type of initial semiconductor. The increase of manganese concentration is shown to result in the formation of smaller CdS-based nanoparticles. Luminescent properties of nanoparticles were studied. The 580 nm peak, which is typical for manganese ions, becomes more distinguished with the increase of their concentration and the time of synthesis.

Investigation of Antioxidant Activity of Pomegranate Juices by Means of Electron Paramagnetic Resonance and UV-Vis Spectroscopy

2015 ◽  
Vol 98 (4) ◽  
pp. 866-870 ◽  
Author(s):  
Violetta Kozik ◽  
Krystyna Jarzembek ◽  
Agnieszka Jędrzejowska ◽  
Andrzej Bąk ◽  
Justyna Polak ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Free Radical ◽  
Epr Spectroscopy ◽  
Antioxidant Properties ◽  
Free Radical Scavenger ◽  
Pomegranate Juice ◽  
Radical Scavenger ◽  
Paramagnetic Resonance ◽  
Vis Spectroscopy ◽  
Electron Paramagnetic

Abstract Pomegranate fruit (Punica granatum L.) is a source of numerous phenolic compounds, and it contains flavonoids such as anthocyanins, anthocyanidins, cyanidins, catechins and other complexes of flavonoids, ellagitannins, and hydrolyzed tannins. Pomegranate juice shows antioxidant, antiproliferative, and anti-atherosclerotic properties. The antioxidant capacity (TEAC) of the pomegranate juices was measured using electron paramagnetic resonance (EPR) spectroscopy and 1,1-diphenyl-2-picrylhydrazyl (DPPH•) as a source of free radicals, and the total phenolic (TP) content was measured using UV-Vis spectroscopy. All the examined pomegranate juices exhibited relatively high antioxidant properties. The TEAC values determined by means of EPR spectroscopy using Trolox (TE) as a free radical scavenger were in the range of 463.12 to 1911.91 μmol TE/100 mL juice. The TP content measured by the Folin-Ciocalteu method, using gallic acid (GA) as a free radical scavenger, widely varied in the investigated pomegranate juice samples and ranged from 1673.62 to 5263.87 mg GA/1 L juice. The strongest antioxidant properties were observed with the fresh pomegranate juices obtained from the fruits originating from Israel, Lebanon, and Azerbaijan. Correlation analysis of numerical data obtained by means of EPR spectroscopy (TEAC) and UV-Vis spectroscopy (TP) gave correlation coefficient (r) = 0.90 and determination coefficient (r2) = 0.81 (P <0.05).

scholarly journals Chain initiation

2019 ◽  
Vol 89 (2) ◽  
pp. 179-186
Author(s):  
V. V. Ptushenko
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Epr Spectroscopy ◽  
Paramagnetic Resonance ◽  
Chain Initiation ◽  
Radio Spectroscopy ◽  
Scientific Instrumentation ◽  
History Of ◽  
Scientists And Engineers ◽  
Electron Paramagnetic

This article describes the formation of the chemical electron paramagnetic resonance (EPR) spectroscopy institute established by Academician Vladislav V. Voevodsky (1917–1967) along with the history of the development of the instrumentation basis for this field of science in the Union of Soviet Socialist Republics (USSR). The design of the first EPR spectrometers for the chemical radio spectroscopy initiated the emergence of a new scientific instrumentation field in this country. Based on recollections shared by scientists and engineers and an examination of archive materials, the author reconstructs relevant events and identifies major participants in this process.

scholarly journals DeerLab: a comprehensive software package for analyzing dipolar electron paramagnetic resonance spectroscopy data

2020 ◽  
Vol 1 (2) ◽  
pp. 209-224 ◽  
Author(s):  
Luis Fábregas Ibáñez ◽  
Gunnar Jeschke ◽  
Stefan Stoll
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Software Package ◽  
Method Development ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Global Analysis ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Least Squares Fit ◽  
Wide Range ◽  
Electron Paramagnetic

Abstract. Dipolar electron paramagnetic resonance (EPR) spectroscopy (DEER and other techniques) enables the structural characterization of macromolecular and biological systems by measurement of distance distributions between unpaired electrons on a nanometer scale. The inference of these distributions from the measured signals is challenging due to the ill-posed nature of the inverse problem. Existing analysis tools are scattered over several applications with specialized graphical user interfaces. This renders comparison, reproducibility, and method development difficult. To remedy this situation, we present DeerLab, an open-source software package for analyzing dipolar EPR data that is modular and implements a wide range of methods. We show that DeerLab can perform one-step analysis based on separable non-linear least squares, fit dipolar multi-pathway models to multi-pulse DEER data, run global analysis with non-parametric distributions, and use a bootstrapping approach to fully quantify the uncertainty in the analysis.

A Study of V3+/4+ Levels in Semi-insulating 6H-SiC using Optical Admittance and Electron Paramagnetic Resonance Spectroscopies

2006 ◽  
Vol 911 ◽  
Author(s):  
Wonwoo Lee ◽  
Mary E Zvanut
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Charge State ◽  
Conduction Band ◽  
Epr Spectroscopy ◽  
Admittance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Characteristic Spectrum ◽  
Epr Measurements ◽  
The Individual ◽  
Electron Paramagnetic

AbstractThe purpose of this study is to identify the vanadium acceptor levels in semi-insulating (SI) 6H-SiC using optical admittance spectroscopy (OAS) and electron paramagnetic resonance (EPR) spectroscopy. OAS conductance peaks near at 0.67 ± 0.02 eV and 0.70 ± 0.02 eV are identified as V3+/4+ levels at the quasi-cubic sites. An OAS peak at 0.87 eV is assigned to the same transition at the hexagonal site. EPR measurements before illumination revealed the characteristic spectrum of V3+. The presence of the V3+ signal supports the identification of the OAS peaks as transitions from the V3+/4+ level to the conduction band. Photo-induced EPR measurements reveal a change in the intensity of V3+ and V4+ at 0.8 ± 0.1 eV, where the amplitude of the V3+ charge state decreases and that of V4+ increases by approximately equal amounts. Although the individual sites are not resolved in the photo-induced EPR data, the 0.8 eV feature strongly supports the assignment of the three OAS peaks as acceptor levels.

scholarly journals Posttranscriptional site-directed spin labeling of large RNAs with an unnatural base pair system under non-denaturing conditions

2020 ◽  
Vol 11 (35) ◽  
pp. 9655-9664
Author(s):  
Yan Wang ◽  
Venkatesan Kathiresan ◽  
Yaoyi Chen ◽  
Yanping Hu ◽  
Wei Jiang ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Epr Spectroscopy ◽  
Base Pair ◽  
Spin Labeling ◽  
Paramagnetic Resonance ◽  
Site Directed Spin Labeling ◽  
Electron Paramagnetic

Site-directed spin labeling (SDSL) of large RNAs for electron paramagnetic resonance (EPR) spectroscopy has remained challenging to date.

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