Paramagnetic centers with S=5/2 in irradiated natural diamonds

1978 ◽  
Vol 19 (2) ◽  
pp. 327-328
Author(s):  
V. A. Nadolinnyi ◽  
M. Ya. Shcherbakova ◽  
E. V. Sobolev
Keyword(s):  
Paramagnetic Centers ◽  
Natural Diamonds

Nitrogen concentration and anisotropic effects on the EPR spectra of natural diamonds

CrystEngComm ◽  
2021 ◽  
Author(s):  
Ira Litvak ◽  
Haim Cohen ◽  
Yaakov Anker ◽  
Sharon Ruthstein
Keyword(s):  
Epr Spectroscopy ◽  
Nitrogen Concentration ◽  
Epr Spectra ◽  
Paramagnetic Centers ◽  
Natural Diamonds

EPR spectroscopy of pre-color treated natural diamonds – yellow and green: correlation between natural pre colored diamond paramagnetic centers and nitrogen concentration.

The value of Electron Microscope studies of imperfect natural diamonds

1990 ◽  
Vol 48 (4) ◽  
pp. 194-195
Author(s):  
J C Walmsley ◽  
A R Lang
Keyword(s):  
Electron Microscope ◽  
Classification Scheme ◽  
Natural Diamond ◽  
Sudden Change ◽  
Growth Conditions ◽  
Diamond Growth ◽  
Major Constituent ◽  
Natural Diamonds ◽  
Type Ia ◽  
Platelet Defects

Interest in the defects and impurities in natural diamond, which are found in even the most perfect stone, is driven by the fact that diamond growth occurs at a depth of over 120Km. They display characteristics associated with their origin and their journey through the mantle to the surface of the Earth. An optical classification scheme for diamond exists based largely on the presence and segregation of nitrogen. For example type Ia, which includes 98% of all natural diamonds, contain nitrogen aggregated into small non-paramagnetic clusters and usually contain sub-micrometre platelet defects on {100} planes. Numerous transmission electron microscope (TEM) studies of these platelets and associated features have been made e.g. . Some diamonds, however, contain imperfections and impurities that place them outside this main classification scheme. Two such types are described.First, coated-diamonds which possess gem quality cores enclosed by a rind that is rich in submicrometre sized mineral inclusions. The transition from core to coat is quite sharp indicating a sudden change in growth conditions, Figure 1. As part of a TEM study of the inclusions apatite has been identified as a major constituent of the impurity present in many inclusion cavities, Figure 2.

An investigation of impurity centers of gem quality natural diamonds by IR-spectroscopy

2021 ◽  
Author(s):  
Mikhail A. Ivanov ◽  
Marina A. Fedotova ◽  
Fedor F. Protopopov ◽  
Semyon P. Leontyev
Keyword(s):  
Ir Spectroscopy ◽  
Natural Diamonds ◽  
Impurity Centers

Photoinduced Paramagnetic Centers in Nanocomposites Formed by Titanium Dioxide and Myristic Acid

2021 ◽  
Vol 125 (12) ◽  
pp. 6773-6786
Author(s):  
Claudio José Magon ◽  
Harold Lozano Zarto ◽  
José Pedro Donoso ◽  
Hellmut Eckert ◽  
Sindy Devis ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Myristic Acid ◽  
Paramagnetic Centers

Jellyfish-like few-layer graphene nanoflakes: high paramagnetic response alongside increased interlayer interaction

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexander Ulyanov ◽  
Dmitrii Stolbov ◽  
Serguei Savilov
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Sensitivity ◽  
Paramagnetic Centers ◽  
Interlayer Interaction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Graphene Nanoflakes ◽  
Few Layer Graphene ◽  
Electron Paramagnetic ◽  
Hydrocarbon Pyrolysis

Abstract Jellyfish-like graphene nanoflakes (GNF), prepared by hydrocarbon pyrolysis, are studied with electron paramagnetic resonance (EPR) method. The results are supported by X-ray photoelectron spectroscopy (XPS) data. Oxidized (GNFox) and N-doped oxidized (N-GNFox) flakes exhibit an extremely high EPR response associated with a large interlayer interaction which is caused by the structure of nanoflakes and layer edges reached by oxygen. The GNFox and N-GNFox provide the localized and mobile paramagnetic centers which are silent in the pristine (GNF p ) and N-doped (N-GNF) samples. The change in the relative intensity of the line corresponding to delocalized electrons is parallel with the number of radicals in the quaternary N-group. The environment of localized and mobile electrons is different. The results can be important in GNF synthesis and for explanation of their features in applications, especially, in devices with high sensitivity to weak electromagnetic field.

scholarly journals Studies of transmembrane peptides by pulse dipolar spectroscopy with semi-rigid TOPP spin labels

2021 ◽  
Author(s):  
Igor Tkach ◽  
Ulf Diederichsen ◽  
Marina Bennati
Keyword(s):  
Molecular Level ◽  
Dipolar Interaction ◽  
Spin Labels ◽  
Paramagnetic Centers ◽  
Structural Adaptation ◽  
Paramagnetic Resonance ◽  
Transmembrane Peptides ◽  
Distance Distributions ◽  
Lipid Environment ◽  
Electron Paramagnetic

AbstractElectron paramagnetic resonance (EPR)-based pulsed dipolar spectroscopy measures the dipolar interaction between paramagnetic centers that are separated by distances in the range of about 1.5–10 nm. Its application to transmembrane (TM) peptides in combination with modern spin labelling techniques provides a valuable tool to study peptide-to-lipid interactions at a molecular level, which permits access to key parameters characterizing the structural adaptation of model peptides incorporated in natural membranes. In this mini-review, we summarize our approach for distance and orientation measurements in lipid environment using novel semi-rigid TOPP [4-(3,3,5,5-tetramethyl-2,6-dioxo-4-oxylpiperazin-1-yl)-L-phenylglycine] labels specifically designed for incorporation in TM peptides. TOPP labels can report single peak distance distributions with sub-angstrom resolution, thus offering new capabilities for a variety of TM peptide investigations, such as monitoring of various helix conformations or measuring of tilt angles in membranes. Graphical Abstract

CO and NH3 sensor properties and paramagnetic centers of nanocrystalline SnO2 modified by Pd and Ru

2011 ◽  
Vol 520 (3) ◽  
pp. 904-908 ◽  
Author(s):  
A.V. Marikutsa ◽  
M.N. Rumyantseva ◽  
A.M. Gaskov ◽  
E.A. Konstantinova ◽  
D.A. Grishina ◽  
...  
Keyword(s):  
Paramagnetic Centers ◽  
Sensor Properties ◽  
Nh3 Sensor

Nonisothermal relaxation of photosensitive paramagnetic centers in A2B6 compounds

1974 ◽  
Vol 21 (4) ◽  
pp. 1338-1341
Author(s):  
F. F. Kodzhespirov ◽  
M. F. Bulanyi ◽  
V. I. Volozov
Keyword(s):  
Paramagnetic Centers
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