Magnetic nuclear spin-echo

McCall, D. W., Douglass, D. C., and Anderson, E. W. (1963). Self-diffusion study by means of nuclear magnetic resonance spin-echo technique. Ber. Bunsenges. Phys. Chem. 67, 336-340. 

R. A. Assink, "A quadrupolar coil for nuclear magnetic resonance spin-echo diffusion measurements as a function of pressure," J. Magn. Resonance 22, 165-168 (1976). 

While the nuclear magnetic resonance (NMR) technique has widely been used to study diffusion processes of normal liquids, solids, or colloidal systems, there are only a few applications to molten salts. The spin echo self-diffusion method with pulsed field gradients was applied to molten salts by Herdlicka et al. "" There is no need to set up or maintain a concentration gradient. 

Pulse Field Gradient Spin Echo-Nuclear Magnetic Spectroscopy Pyridyl... 

J. D. Seymour, B. Manz, P. T. Callaghan 1999, (Pulsed gradient spin echo nuclear magnetic resonance measurements of... 

The presence of four kinds of nuclear magnetic resonance (NMR) observable nuclei ( H, uB, 13C, and 29Si) allows poly(m-carborane-siloxane) to be readily investigated using NMR spectroscopy. In addition, H spin-echo NMR relaxation techniques can provide an insight into polymer segmental chain dynamics and therefore useful information on material viscoelastic characteristics. 

We describe in some detail the techniques of nuclear magnetic resonance which are used for studying alumina-supported platinum catalysts. In particular, we describe the spin-echo technique from which the Pt lineshape can be obtained. We also discuss spin echo double resonance between surface Pt and chemisorbed molecules and show how the NMR resonance of the surface Pt can be separately studied. We present examples of experimental data and discuss their interpretation. 

Electron-nuclear double resonance (ENDOR) spectroscopy A magnetic resonance spectroscopic technique for the determination of hyperfine interactions between electrons and nuclear spins. There are two principal techniques. In continuous-wave ENDOR the intensity of an electron paramagnetic resonance signal, partially saturated with microwave power, is measured as radio frequency is applied. In pulsed ENDOR the radio frequency is applied as pulses and the EPR signal is detected as a spin-echo. In each case an enhancement of the EPR signal is observed when the radiofrequency is in resonance with the coupled nuclei. 

Electron nuclear double resonance (ENDOR) and electron spin-echo envelope modulation (ESEEM) are two of a variety of pulsed EPR techniques that are used to study paramagnetic metal centers in metalloenzymes. The techniques are discussed in Chapter 4 of reference la and will not be discussed in any detail here. The techniques can define electron-nuclear hyperfine interactions too small to be resolved within the natural width of the EPR line. For instance, as a paramagnetic transition metal center in a metalloprotein interacts with magnetic nuclei such as H, H, P, or these... 

The reduction of obtainable light-pulse durations down to subpicosecond pulses (halfwidth about 10 sec) allows fast transient phenomena which were not accessible before to be studied in the interaction of light with matter. One example is the extension of spin echoe-techniques, well known in nuclear-magnetic-resonance spectroscopy, to the photon echoes in the optical region. 

For the pressure studies, two phase" compact ion behavior is observed with an inflection point between 7 and 11 atms. For the aqueous solution studies, the hydraulic permeability K and the g-ratio are hardly effected by solute type (within experimental error). The solute diffusive permeability however, varies with solute type in good qualitative agreement with free energy parameters, infrared overtone shifts, and spin echo and continuous wave nuclear magnetic resonance spectroscopy results from the literature. 

ESEEM is a pulsed EPR technique which is complementary to both conventional EPR and ENDOR spectroscopy(74.75). In the ESEEM experiment, one selects a field (effective g value) in the EPR spectrum and through a sequence of microwave pulses generates a spin echo whose intensity is monitored as a function of the delay time between the pulses. This resulting echo envelope decay pattern is amplitude modulated due to the magnetic interaction of nuclear spins that are coupled to the electron spin. Cosine Fourier transformation of this envelope yields an ENDOR-like spectrum from which nuclear hyperfine and quadrupole splittings can be determined. 

The rehydrated samples were obtained by exposing dehydrated samples to water vapor at least three days over saturated NH4GI solution at room temperature. A duraction of 0.5 s between scans were allowed for nuclear spin to recover to their equilibrium magnetization. The one—dimensional Na NMR spectra were recorded by using the spin—echo technique. The strength of the radio-frequency field for the two dimensional nutation experiments was 80 kHz and 128 ti values were used (0 250 /is). Each two- dimensional experiment took about 12 hours of spectrometer time. 

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