Electron paramagnetic resonance temperature effects

Nuclear magnetic resonance spectroscopy of the solutes in clathrates and low temperature specific heat measurements are thought to be particularly promising methods for providing more detailed information on the rotational freedom of the solute molecules and their interaction with the host lattice. The absence of electron paramagnetic resonance of the oxygen molecule in a hydroquinone clathrate has already been explained on the basis of weak orientational effects by Meyer, O Brien, and van Vleck.18... 

Selected entries from Methods in Enzymology [vol, page(s)] Electron paramagnetic resonance [effect on line width, 246, 596-598 motional narrowing spin label spectra, 246, 595-598 slow motion spin label spectra, 246, 598-601] helix-forming peptides, 246, 602-605 proteins, 246, 595 Stokes-Einstein relationship, 246, 594-595 temperature dependence, 246, 602, 604. 

However, these reactions are also second order in N02 and appear to be too slow at atmospheric NOz levels to be important (Vogt and Finlayson-Pitts, 1994 Peters and Ewing, 1996). There is one aspect of the mechanism that is quite interesting, however, in that the mechanism appears to be at least in part a stepwise process involving the formation of a radical anion intermediate, C1---N02 in the solid, which has been identified by electron paramagnetic resonance (EPR) in both the NaCl and NaBr reactions at room temperature (Wan et al., 1996). This intermediate appears to be remarkably stable and may be responsible for synergistic health effects observed when rats were exposed to a combination of N02 and NaCl aerosols (Last and Warren, 1987). 

Fig. 5. Energy above the valence band of levels reported in the literature for GaP. Arrangement and notations are the same as in Fig. 4. Abbreviations for experimental methods not defined in Fig. 4. are temperature dependence of resistivity (RT), temperature dependence of minority-carrier lifetime (LT), Hall effect (H), and photostimulated electron paramagnetic resonance (PEPR).

The temperature dependence of the magnetic complex conformation is known to be one of the distinguishable features of Jahn-Teller (JT) dynamics [1]. Keeping in mind electron paramagnetic resonance (EPR) as one of the most effective methods of studying the JT effect, we shall consider the problem of the transition from the low temperature, static JT situation to the high temperature, dynamic, motional averaged JT situation. The results of such processes are discussed in the literature [1-4]. At the same time, some important features - the nature of the transitions... 

Electron paramagnetic resonance (EPR) measurements for actinide ions are usually made at liquid-helium temperatures in order to lengthen the spin-4attice relaxation time (Tj) so the resonance may be observed [7,8]. Consequently information is obtained only about the ground crystal field state and possibly the first excited state. The spectra are interpreted in terms of an effective spin Hamiltonian ... 

No stable divalent salt is known. However, Am2+ has been detected in CaF2 matrix (0.1% Am) by paramagnetic resonance spectrum at low temperature. Its formation is attributed to the reduction of Am3+ by electrons in the lattice set free by the effects of alpha particle emission. 

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