Inhomogeneous rf Field

Gerlioh D 1992 Inhomogeneous RF fields a versatile tool for the study of prooesses with slow ions State-Selected and State-to-State Ion-Molecule Reaction Dynamics Part 1. Experiment ed C Ng and M Baer (New York Wiley)... 

Quadmpoles or hexapoles are used as transmission guides for both slow and fast ions. In both cases, the objective is to ensure that as many ions as possible are guided from the entrance of the device to its exit. The ions are usually in transit in a straight line between an ion source and a mass analyzer. Any ions within the transmission guides that are deflected from the desired trajectory are pushed or pulled back on course by the action of the inhomogeneous RF fields applied to the poles of the guides. 

Chapter 49 Transmission of Ions through Inhomogeneous RF Fields... 

Gerlich, D. 1992. Inhomogeneous RF fields A versatile tool for the study of processes with slow ions. Adv. Chem. Phys. 82 1-176. 

An alternative approach for the elimination of zero-quantum coherence is based on its evolution during periods of spin-locking in inhomogeneous Bq or Bj fields (Titman et al., 1990 Davis et al., 1993). This approach is particularly attractive, because it does not rely on time-consuming phasecycling schemes and variation of z-filter delays. Consider an inhomogeneous rf field with amplitude I f (r) that depends on the position r in the... 

The inhomogeneity in Bi, especially when using surface coils, can lead to a spatially dependent population of desired and undesired coherence pathways. Field gradient pulses in combination with shaped RF pulses lead to spatially selective excitation or refocusing and, in such cases, localization can be viewed as a type of coherence pathway selection. The inherent Bi gradients resulting from the inhomogeneous RF fields of surface coils have also been used for water suppression in in vivo experiments. ... 

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