Inhomogeneity B! field

Despite the inhomogeneous B field of the siuface coil, spin-lock experiments can also be performed to interrogate 7 ip relaxation (cf. Sections 3.5 and 7.2.3) [Blii2]. If Tc denotes the correlation time of molecular motion then, from eqn (3.5.7) Tip can be expressed in the weak collision limit as... 

A MBER spectrometer is shown schematically in figure C1.3.1. The teclmique relies on using two inhomogeneous electric fields, the A and B fields, to focus the beam. Since the Stark effect is different for different rotational states, the A and B fields can be set up so that a particular rotational state (with a positive Stark effect) is focused onto the detector. In MBER spectroscopy, the molecular beam is irradiated with microwave or radiofrequency radiation in the... 

Composite pulse A composite sandwich of pulses that replaces a single pulse employed to compensate for B] field inhomogeneities, phase errors, or offset effects. 

B. Approaches Based on Ab Initio Calculations on a Single Water Molecule in an Inhomogeneous Electric Field... 

Eujiwara, M. Chie, K. Sawai, J. Shimizu, D. Tanimoto, Y. On the Movement of Paramagnetic Ions in an Inhomogeneous Magnetic Field. J. Phys. Chem. B 2004, 108, 3531-3534. 

Fig. 49 a and b. Diagrammatic representation of a neutral particle in an inhomogeneous electric field, a) the particles are able to migrate, because the field intensity is not equal on both sides resulting in a net force so-called dielectrophoresis, b) The direction of dielectrophoresis is independent of the polarity of the field. In an alternating field all particles will move in the direction of higher field strengths 611... 

Depending on the type of boundary and field, a force may act on the static interface. This can be seen from Figure 10-8. For the analysis, let us place the crystal between asymmetric capacitor plates. Without the field, the boundary (b) is surrounded by a symmetric (AX/AX) or an asymmetric (AX/AY) space charge. Thus, an inhomogeneous electric field exerts a force on the (dipolar) interface. The boundary... 

Figure 10-8. Schematic diagram of a device for the determination of interface mobility in an inhomogeneous electric field. The motion due to electric (and frictional) forces occurs a) without, b) with galvanic contact (inducing ionic fluxes and decomposition of AX).

Consider the formation of a spin echo following a 180° pulse applied to a spin system consisting of two protons, (a) Assume that the protons have the same chemical shift (as in H20, for example). Explain why the echo forms and eliminates the effect of magnetic field inhomogeneity, (b) Assume that the two protons differ in chemical shift but are not spin... 

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