Conventional electron paramagnetic resonance

Electron paramagnetic resonance spectroscopy, also known as electron spin resonance (ESR) spectroscopy, detects the excitation of electron spins in an applied external magnetic field.13 Conventional continuous-wave (CW) EPR is based on resonance of a fixed-frequency standing microwave to excite some of the electrons in Zeeman-split spin multiplets to undergo a transition from a lower Ms level to a higher... 

The conventional method for determining cation ordering and site populations within a crystal structure is by diffraction techniques using X-ray, electron and neutron sources. For determining site occupancies of transition metal ions, these methods have been supplemented by a variety of spectroscopic techniques involving measurements of Mossbauer, electron paramagnetic resonance (EPR or ESR), X-ray absorption (EXAFS and XANES), X-ray photoelectron (XPS), infrared and optical absorption spectra. 

A118. Valavanidis, A. and E. Haralambous A comparative smdy by electron paramagnetic resonance of free radical species in the mainstream and sidestream smoke of cigarettes with conventional acetate filters and bio-filters Redox Report 6 (2001) 161-171. 

Magnetic resonance plays a role in biophysical spectroscopy of ever increasing importance and diversity. The topic is conveniently and conventionally divided into three domains (1) nuclear magnetic resonance (NMR) spectroscopy, (2) Mdssbauer spectroscopy, and (3) electron paramagnetic resonance (EPR) spectroscopy. All three of these methods depend on the presence of a magnetic moment, either that of a nucleus or of an unpaired electron. This overview is confined to the topic of EPR as the biological applications of NMR are so extensive that they receive dedicated reviews (e.g.. Volume 239 in this series) and the biochemical applications of Mdssbauer spectroscopy have been reviewed elsewhere in this series. ... 

Chemically modified celluloses have been analyzed by conventional wet methods and by various Instrumental methods designed to differentiate bulk and surface properties. Electron emission spectroscopy for chemical analyses (ESCA) used alone and In combination with radiofrequency cold plasmas yielded elemental analyses, oxidative states of the element, and distribution of the element. Techniques of electron paramagnetic resonance (EPR), chemiluminescence, reflectance infrared spectroscopy, electron microscopy, and energy dispersive X-ray analyses were also used to detect species on surfaces and to obtain depth profiles of a given reagent in chemically modified cottons. 

Electron paramagnetic resonance (EPR) studies in a conventional X-band spectrometer showed the following ... 

Resonance Raman and antisymmetric scattering are involved in a novel technique involving spin-flip Raman transitions in paramagnetic molecules that can function as Raman electron paramagnetic resonance. Figure 3.2a shows a conventional vibrational Stokes resonance Raman process, while 3.2b and 3.2c show the polarization characteristics of the two distinct spin-flip Raman processes for scattering at 90°... 

Because some of the forms of heme proteins are intrinsically paramagnetic, electron paramagnetic resonance (EPR) has been used extensively to study the stracture and structure-function relations of these proteins. By far the majority of these investigations are done using continuous-wave (cw) EPR at the conventional X-band microwave frequency ( 9.5 GHz), and these cw-EPR studies have formed the basis of many excellent reviews [4-6]. In the last two decennia, the field of EPR spectroscopy has, however, been revolutionized by many technical developments. Indeed, the construction of pulse-EPR spectrometers, die accompanying developments of the pulse-EPR methodology, and the (ongoing) development of... 

Quite unusual reaction order in respect to initiator suggests that termination reaction is more complicated than that in conventional pol3mietization. The process of radical termination by electron paramagnetic resonance (EPR) technique. EPR spectra for multimethacrylate in dioxane, after illumination of UV for 5 min and then switching off the light source were recorded. 

For example, Vo has a very high formation energy in n-type ZnO (the Fermi level close to the conduction band), even under extreme Zn-rich conditions. Therefore, Vq concentration should be very low under equilibrium conditions in as-grown undoped ZnO. Moreover, Vo is a deep rather than a shallow donor and it carmot be responsible for n-type conductivity of undoped ZnO, contrary to the conventional wisdom dominated in ZnO communities for decades. In contrast, the anion vacancies can be formed abundantly in p-type material and may be the main cause of the selfcompensation. It should also be noted that Vq in n-type material can be formed after electron irradiation. Electron paramagnetic resonance studies indeed revealed the presence of Vo in electron irradiated ZnO as a signal with g= 1.99 [92-94]. 

Finally, ONP may be achieved with the aid of applied electromagnetic (i.e., radiofrequency, rf or microwave, mw) fields (c), and thus can most simply be considered as extensions of conventional DNP methods these approaches are referred to as radio-frequency induced ONP (RFONP) and microwave-induced ONP (MIONP), respectively. In conventional DNP, magnetization from thermally polarized electron spins (residing, for example, in permanent paramagnetic centers) is driven via hyperfine interactions to surrounding nuclei using resonant or near-resonant AC fields. More specifically, this process is governed by the conventional Overhauser effect in the case of dynamic hyperfine interactions (e.g., in metals or semiconductors),... 

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