Zeeman system

In spin relaxation theory (see, e.g., Zweers and Brom[1977]) this quantity is equal to the correlation time of two-level Zeeman system (r,). The states A and E have total spins of protons f and 2, respectively. The diagram of Zeeman splitting of the lowest tunneling AE octet n = 0 is shown in fig. 51. Since the spin wavefunction belongs to the same symmetry group as that of the hindered rotation, the spin and rotational states are fully correlated, and the transitions observed in the NMR spectra Am = + 1 and Am = 2 include, aside from the Zeeman frequencies, sidebands shifted by A. The special technique of dipole-dipole driven low-field NMR in the time and frequency domain [Weitenkamp et al. 1983 Clough et al. 1985] has allowed one to detect these sidebands directly. 

All instruments should be equipped with a background correction facility. Virtually all instruments now have a deuterium arc background correction. The Zeeman system is also available in instruments marketed by the Perkin-Elmer Corporation and the Smith-Hieftje system by Thermo Electron Ltd. 

The second step of the evolution towards equilibrium is the Zeeman dipole-dipole relaxation. Hartmann and Anderson estimated this time using the hypothesis that p at any time is of the form (22). As a consequence of the shortness of the dipole-dipole relaxation time we may assume that the dipole-dipole system always remains in equilibrium we are thus led to treat the evolution of the Zeeman system as the Brownian motion of a collective coordinate in the dipole-dipole heat bath. We assume that the diagonal elements of p have the form... 

In many modern atomic absorption spectrometers, this correction may be done automatically and simultaneously, time resolution of a few milliseconds being used to separate the two signals. Careful co-alignment of the two source beams is very important. To overcome this need, two other background correction systems have come into use over recent years, the Smith-Hieftje system and the Zeeman system. 

Provided that the system is in a high field Hq, and that no rf fields are applied on resonance, the dipolar ordered system and the Zeeman system are isolated from each other, the only connection being through the lattice. The dipolar... 

In the B panel the matrix overlaps the analyte emission line with no magnetic field. When the magnetic field is applied, this overlap is reduced and the matrix will have been undercorrected by the Zeeman system. In this case the matrix will cause a signal even when no analyte is present. 

Matrix effects are minimal provided sufficient ashing at 1100 °C is used. As indicated previously, background is a problem and Zeeman systems are preferable (Pleban and Pearson. 1979 Neve and Leclerq. 1991). With deuterium-arc background correction, greater attention has to be paid to the design of the programme to reduce background. 

The TM effect is less efficient compared to the CE. The TM can be described by a series of interacting systems the electron Zeeman system (EZS), the electron dipolar system (EDS), and the nuclear Zeeman system (NZS) [19]. 

Magnetic circular dicliroism (MCD) is independent of, and thus complementary to, the natural CD associated with chirality of nuclear stmcture or solvation. Closely related to the Zeeman effect, MCD is most often associated with orbital and spin degeneracies in cliromophores. Chemical applications are thus typically found in systems where a chromophore of high symmetry is present metal complexes, poriihyrins and other aromatics, and haem proteins are... 

In the previous section it has been shown that the measured sample absorbance may be higher than the true absorbance signal of the analyte to be determined. This elevated absorbance value can occur by molecular absorption or by light scattering. There are three techniques that can be used for background correction the deuterium arc the Zeeman effect and the Smith-Hieftje system. 

This adiabatic principle was one of the corner-stones of the old quantum theory. It allowed one to find the quantum conditions when an adiabatic change was imposed on a system. It was used successfully to account for the Stark and Zeeman effects in the spectrum of atomic hydrogen, resulting from the application of an electric and magnetic field respectively (Schwartzchild [1916] Epstein [1916]). 

The spin state of a paramagnetic system with total spin S wiU lift its (25 + l)-fold degeneracy under the influence of ligand fields (zero-field interaction) and applied fields (Zeeman interaction). The magnetic hyperfine field sensed by the iron nuclei is different for the 25 + 1 spin states in magnitude and direction. Therefore, the absorption pattern of a particular iron nucleus for the incoming synchrotron radiation and consequently, the coherently scattered forward radiation depends on how the electronic states are occupied at a certain temperature. 

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