Nuclear energy field strength

This expression provides the basis of a spectroscopic method The transition of electron or nuclear spins between energy levels ("change of spin") may be associated with the emission or absorption of energy in the form of radiation with the appropriate frequency. Since the frequency is proportional to the applied field, spin spectra can in principle be studied in any region of the electromagnetic spectrum, merely by choosing an appropriate field strength. For practical reasons the fields are normally of the order of 1.5 tesla for nuclei and 0.3 tesla for electrons. 

In the spectrum you see above, each peak represents a different kind of carbon atom each one absorbs energy (or resonates—hence the term nuclear magnetic resonance) at a different frequency. But why should carbon atoms be different We have told you two factors that affect the energy difference (and therefore the frequency)—the magnetic field strength and what sort of nucleus is being studied. So you might expect all carbon-13 nuclei to resonate at one particular frequency and all protons ( H) to resonate at one (different) frequency. But they don t. 

In order to obtain a statistical measure for the ionization process we have calculated for an ensemble of trajectories the fraction of ionized orbits as a function of time. The initial internal energy was chosen to correspond to a completely chaotic phase space of the He -ion if the nuclear mass were infinite. The initial conditions for the internal motion have been selected randomly on the energy shell. In Fig. 11 we have illustrated the fraction of ionized orbits as a function of time up to T = 10 a.u. for a series of different CM energies and for a very strong laboratory field strength of B = 10 a.u.. For an initial CM energy of Ec = 0.053 a.u. which corresponds to an initial CM... 

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