Nuclear magnetic resonance resonant frequency

The NMR gaussmeter (or teslameter, to be "modem") detects the nuclear magnetic resonance frequency v of protons in a water sample in the field being measured ... 

For chemically interesting nuclei, Table 11.10 lists values of the nuclear spin quantum number I, the nuclear gyromagnetic ratio gN/ the nuclear electric quadrupole moment Q, and the nuclear magnetic resonance frequency v (Hz, for H0 = 1 tesla). 

Proctor WG, Yu FC. 1950. The dependence of a nuclear magnetic resonance frequency upon chemical compound. Phys Rev 77 717. 

Proctor, W.G. Yu, F.C. 1950, The Dependence of a Nuclear Magnetic Resonance Frequency Upon Chemical Compound , Physical Review, 77, 717. 

Fig. 2. Qualitative variation of the nuclear magnetic resonance frequency with the strength of an applied external field for a spherical ferromagnetic sample with negligible magnetic anisotropy and isotropic, positive hyperfine field at low temperature (saturated magnetization).

Whereas the paramagnetic shift of the nuclear magnetic resonance frequency for a given applied field is related to the strength of the local hyperfine field at the nuclear site, induced by the electronic moments, the nuclear spin-lattice relaxation rate yields information about the low-frequency spectrum of thermally induced spin fluctuations. The influence of pair-correlation effects on the NMR relaxation in paramagnets was analysed experimentally and theoretically by... 

Fig. 17. Variation with temperature of the nuclear magnetic resonance frequency (MHz per tesla) of " Ho (/ = j) inCsjNaHoCle (Bleaney et al. 1981a). A points deduced from susceptibility measurement of Hoehn and Karraker (1974).

The nuclear magnetic resonance frequency, (Do, of a sample placed in a magnetic field Bo can be represented by fiie relation... 

Nuclear Magnetic Resonance. The iateraction of a nucleus with Bq is usually described usiag vector notation and models as ia Figure 2 where the bulk magnetization, Af, and the static field Bq are initially parallel to A radio frequency pulse is appHed ia the xy plane for a duration of t p.s,... 

Nuclear magnetic resonance (nmr) requires an atomic nuclei that can absorb a radio-frequency signal impinging it in a strong magnetic field to give a spectmm. The field strength at which the nucleus absorbs is a function of both the nucleus and its immediate electronic environment. The atoms normally used for nmr analysis are as follows (34) H, F, P, Si, and Of these, the most commonly used in polymer analyses are... 

Isotope Nuclear spin Resonance frequency, MH2 Relative sensitivity Magnetic moment, 10 j/t ... 

In this chapter, three methods for measuring the frequencies of the vibrations of chemical bonds between atoms in solids are discussed. Two of them, Fourier Transform Infrared Spectroscopy, FTIR, and Raman Spectroscopy, use infrared (IR) radiation as the probe. The third, High-Resolution Electron Enetgy-Loss Spectroscopy, HREELS, uses electron impact. The fourth technique. Nuclear Magnetic Resonance, NMR, is physically unrelated to the other three, involving transitions between different spin states of the atomic nucleus instead of bond vibrational states, but is included here because it provides somewhat similar information on the local bonding arrangement around an atom. 

If the oriented nuclei are now irradiated with electromagnetic radiation of the proper frequency, energy absorption occurs and the lower-energy state "spin-flips" to the higher-energy state. When this spin-flip occurs, the magnetic nuclei are said to be in resonance with the applied radiation—hence the name nuclear magnetic resonance. 

Wachtell (Ref 23) worked on the application of this principle. However, early in his work a major problem was encountered in finding the quadrupole resonance of the chlorine nucleus which did not exist in the frequency range in which it had been expected (20—40 megacycles). Nuclear Magnetic Resonance studies finally have shown that this quadrupole resonance should exist around 150 kilocycles. Future studies of single crystals of AP should reveal the presence and the exact location of this resonance. If this can be done, then the analysis of particle size, based on the shift of the quadrupole resonance frequency, may be possible... 

The best approach to the simultaneous determination of ingredients of a phosphorus-containing surfactant is by nuclear magnetic resonance [306]. To 1 ml of the solution of the sample exactly 1.7 ml tetrahydrofuran and 0.3 ml deuteroacetone, >99 %D, are placed into a homogeneously strong magnetic field and excited by a high-frequency radiation typical of phosphorus. 

A solid-state nuclear magnetic resonance (NMR) experiment was carried out in 4 mm double bearing rotor made from Zr02 on a Bruker DSX 200 MHz spectrometer with resonance frequency at 75.468 MHz. The pulse length was 3.5 ps and the contact time of IH-13C CP was 2-5 ms. 

A field of application of MD that is beginning to bear fruit is the refinement of data from nuclear magnetic resonance (NMR) and from diffraction experiments. High-resolution NMR at frequencies around 500 MHz is able to resolve individual proton resonances of biological macromolecules in solution with molecular weights exceeding 10,000... 

Given their radio-frequency electrical properties and nuclear magnetic resonance chemical shift components, solutions of reversed micelles constituted of water, AOT, and decane have been proposed as suitable systems to test and calibrate the performance of magnetic resonance imagers [68]. 

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