Phase shift spin polarized

Figure 6.2. (I) Conventional phosphorescence spectrum of 2,3-dichloroquinoxa-line in durene at 1.6°K. (II) am-PMDR spectrum, obtained by amplitude modulation of microwave radiation that pumps the tv-t, (1.055 GHz) zf transition with the detection at the modulation frequency. Only bands whose intensities change upon microwave radiation (1.055 GHz) and thus originate from tv or rz appear in the am-PMDR spectrum. Transitions from r and rv appear with opposite sign (phase-shifted by 180°). (Hb, lie ) Polarization of the am-PMDR spectral transitions, relative to the crystal axes. The band at 0,0-490 cm-1 originates from both the r and t spin states its intensity does not change upon the 1.055-GHz saturation (no band in II) however, its polarization does rhanp. (bands in Hb and IIc ). (Reproduced with permission from M. A. El-Sayed.tt7W)...

Charge density-NMR chemical shift correlation in organic ions, 11, 125 Charge distribution and charge separation in radical rearrangement reactions, 38, 111 Chemically induced dynamic nuclear spin polarization and its applications, 10, 53 Chemiluminesance of organic compounds, 18, 187 Chiral clusters in the gas phase, 39, 147... 

Fig. 10.4) it has been noticed that opposite phase shifts during phase cycling have to be implemented on Varian instruments when compared to Bruker, since phase shifts have been implemented differently by the spectrometer manufacturers). The remaining antiecho polarization transfer pathway, 5 - 13 connects a single transition of spin S with... 

The phase shifts <5, are calculated by standard partial-wave scattering theory. It involves the electron-atom interaction potential of the muffin-tin model. There are a variety of ways to obtain this potential, which consists of electrostatic and exchange parts (spin dependence may be included, especially when the spin polarization of the outgoing electrons is of interest). One usually starts from known atomic wave functions within one muffin-tin sphere and spherically averages contributions to the total charge density or potential from nearby... 

An example of a velocity-encoding method is the bipolar-gradient method.35 Here, two identical pulses are applied during the dephasing and rephasing periods of a spin-echo sequence. Since the two pulses are in opposite polarity with respect to the time domain, the phase shift (p(t) in Eq. (28) is dominated by the velocity term, i.e. the first-order term of t in the expansion. 

Finally, in Sect. E the optical and magnetic properties are considered. It is found experimentally that some Zintl phases are colored and in ternary systems the color changes continuously as a function of the composition. This change can be correlated to a shift in a maximum of the imaginary part 2 of the dielectric constant e, and 2 can be interpreted by electronic interband transitions ) The magnetic susceptibility and Knight shift are discussed on the basis of spin polarized band structure calculations . Spin and orbital contributions are also considered. 

The basic scheme for current-density imaging in the laboratory frame is depicted in Fig. 7.4.1 [Seri]. Two current pulses I of total duration tc are applied with opposite polarity in the de- and rephasing periods of a standard spin-echo imaging sequence so that the local phase shifts induced by each of them add constructively. 

The processes that occur during the evolution period are probably the most important in describing the effect of the complete pulse sequence. During this period coherence can evolve, coherence can be selectively manipulated or coherence transfer can occur. Coherence manipulation can be the inversion of the coherence order (WATERGATE experiment) or in a l S spin system a phase shift depending upon signal multiplicity (APT or SEMUT experiment). In the case of heteronuclear IS spin systems the creation of antiphase coherence and subsequent polarization transfer using a INEPT or a DEPT unit can be used in multiplicity edited experiments or heteronuclear 2D correlation experiments. In transient NOE experiments such as ROE and TROESY, coherence... 

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