Deuteron quadrupole splitting

As shown in Figure 10 the water deuteron quadrupole splitting increases with increasing electrolyte concentration. This may well fit with the model discussed above if the postulated conformation change of the polar head groups consists of a stretching out of the choline groups away... 

Figure 10. Water deuteron quadrupole splitting as a function of sodium chloride concentration for the same samples as in Figure 8...

Figure 11. Temperature dependence of the choline-N-C2HS deuteron quadrupole splitting of a lamellar mesophase sample composed of 75 wt % [N-C2HS] dimyristoyllecithin in H20...

The observation of deuteron quadrupole splittings In the deuteron spectra of deuterated aromatic compounds has also been reported In a series of articles by Lohman and Maclean (11.15.16). 

Figure 4. Deuteron resonance decay curve after a 90° pulse for the same sample as in Figure 3. The symbol A represents the measured quadrupole splitting.

The NMR spectrum of p-xylene-d4 (all ring protons are replaced by deuterons) sorbed on ZSM-5 is shown in Fig. 20. From the observed quadrupole splitting of about 140 kHz, it follows that for all molecular mo-... 

Vaara and Pyykko presented a theory for the magnetic-field-dependent quadrupole splitting in the Xe NMR spectra in isotropic media and tested it by ab initio electronic structure calculations. Evidence exists only for even-power magnetic field dependence. The dominant mechanism is verified to be the electric field gradient caused by the diamagnetic distortion of the atomic electron cloud, quadratic in the magnetic field. NQCC for diatomic molecules were calculated by Bryce and Wasylishen. Turner et al performed a systematic computational study of the geometrical dependence of the deuteron quadrupole interaction parameters (DQCC and asymmetry parameter) for the water-formaldehyde model system. Bematowicz and Szymanski studied NMR spectra of a spin nucleus scalar coupled to two equivalent spin-1 nuclei... 

A tensorial NMR parameter suitable for stress and strain imaging is the strain- and orientation-dependent quadrupole splitting of deuterons. Deuter-ated butadiene oligomers have been incorporated into household rub-berbands by swelling in order to apply spectroscopic imaging and doublequantum imaging of deuterons to detect stress and strain distributions under applied strain [82, 83]. 

The H NMR spectrum (1 = 1, Am = 1) of a single deuteron, or of a single crystal where all the C— H bonds are aligned parallel, thus consists of a doublet separated by a quadrupole splitting... 

Deuterium NMR spectroscopy of the discotic phase of hexa-n-hexyloxy triphenylene has led to similar conclusions. Spectra of two selectively deuterated isotopic species, one in which all aromatic positions are substituted and the other in which only the a-carbon side chains are substituted, bring out the difference between the order parameters of the cores and the tails. Fig. 6.1.3 gives the quadrupole splittings of the aromatic and the a-aliphatic deuterons versus temperature in the meso-phase region. It is seen that the rigid core is highly ordered, the orientational order parameter s ranging from 0.95 to 0.90, whereas the a-aliphatic chains are in a disordered state. 

Fig. 6.1.3. Quadrupole splittings for the aromatic and a-aliphatic vj deuterons of deuterated hexa-n-hexyloxytriphenylene (THE6) as functions of temperature (r— 7 ) in the mesophase region, where 7 is the mesophase-isotropic transition point. The open circles correspond to measurements on neat THE6-ard, and THE6-adi2 separately, while the filled circles correspond to a 2 1 mixture of the two isotopic species. The scale on the upper right-hand side gives the orientational order parameter of the aromatic part. The curve at the bottom gives the ratio of the quadrupole splittings for the a-aliphatic and aromatic deuterons (Goldfarb, Luz...

Figure 8.9(a) shows the pulse sequence used to obtain the deuteron exchange powder pattern [59]. The sequence differs from the spin 1/2 version (chapter 6) owing to spin 1 dynamics of the deuteron and the need for quadrupole echo detection to overcome probe ringing. The first two pulses, which bracket the evolution period, provide frequency selection of individual quadrupole splittings. As with the spin 1/2 experiment, in-phase and out-of-phase pulse pairs select the sine and cosine components of the evolving magnetization to yield quadrature detection in the FI dimension. One can use either the hyper-... 

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