Radio-frequency magnetic field

When energy equivalent to the difference between the energy levels is applied to the system, a transition from the lower to the higher energy level occurs. In NMR spectroscopy, the applied energy that allows this nuclear magnetic dipole transition to occur is a radio-frequency magnetic field, Hx, which is applied perpendicularly to H0. 

In continuous-wave experiments (single resonance), the super-Hamiltonian HD includes an additional component which represents interactions with the radio-frequency magnetic field Bx rotating in the same direction as the Larmor precession (21)... 

In the absence of a radio-frequency magnetic field Bx, the density matrix components concerned with an eigenvalue Ff (=k) change with time according to u... 

As mentioned, the line intensities are equal exept for the contribution of the Boltzmann factor, the relaxation times and the orientation of the sample crystallites relative to the radio-frequency magnetic field.They thus deserve no further mention. 

The NQR signal is measured by coupling an oscillating radio-frequency magnetic field H with the magnetic dipole moment of the nucleus (as in... 

Fig. 29. Filter-weighted and spin-lattice relaxation in the rotating frame Tip of an elastomer composite of SBR and natural rubber cut from the tread of a car tire, (a) A stack of one-dimensional images with variable duration tf of the spin-lock radio-frequency magnetic field, (b) A Tip parameter map obtained from the decay shown in (a). Reproduced from Ref 143, with permission from Wiley.

Cb) Transient experiments. When a radio-frequency magnetic field close to the resonance frequency, is suddenly... 

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