Pake-type

Figure 5. NMR spectra of the radial left) and bipolar droplet right) for different values of the diffusion parameter A A = 0 corresponds to the no-diffusion limit, while A = 32 corresponds to the fest diffusion limit. Radial droplet The Pake-type powder spectrum obtained for A = 0 collapses into a single line centered at zero quadrupolar splitting for A = 32. Bipolar droplet The mckgnetic field is aligned along the bipolar symmetry ajds, which results in a spectrum consisting of two lines both in absence of diffusion and in the fest diffusion limit.

We now turn to radial droplets for which, in absence of external fields (with 1) = 0) and for T = 0.8 the hedgehog -like structure is stable. As discussed above, the spectrum of the radial droplet for 7/ = 0 is the Pake-type powder pattern consisting of two asymmetric peaks at S(jJqS [25],... 

NMR spectra of deuterated immobile molecules or their fragments (eg, methyl CD -groups in hydrocarbons) represent Pake-type powder patterns [97,98]. The dominant features of these line shapes are two strong peaks separated by the splitting (3/4)(2(, and two shoulders separated... 

For a random distribution of pp angles in a powder sample, a superposition of the doublets with different splittings gives rise to a Pake-type spectrum [28]. 

One question to be settled is how the formal definition of tensor involves the quality of the vectors projecting onto Y, that is how are products of type ET Y F affected by whether vectors E and F are axial or polar [see Ref. 152, p. 98]. The latter authors, Pake and Estle, make the statement that for example g is not a true tensor due to this characteristic. Our thought is that both axial and polar tensors are tensors as defined by mathematicians. Then too, the question arises if Y is a tensor, how does one decide in practice whether it is an axial tensor or a pseudotensor ... 

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