Starring process INDEX

Here p is the density of phonons, n(co) is the Planck number corresponding to the thermal distribution of phonon excitations and k(co) is the spin-phonon coupling constant written as a function of frequency (instead of the wave-vector star k and the phonon branch index, as previously). Only those phonons with energy equal to the Zeeman energy h coa are of interest in a direct relaxation process. This energy is characteristically 0.1 cm-1 and the relevant phonons are of the long-wave acoustic type. Their role is to modulate the crystal field interacting with the electron. 

Figure 4.40 shows that, for a PE-HD, dispersion index and molecular weight increase due to thermal-oxidative degradation at high processing temperatures (in contrast to their behavior at low temperatures. Fig. 5.158). Radical chain reaction in polyethylenes with unsaturated vinyl groups leads to three- or four-pointed star configurations that cause an increase in shear viscosity. Here, chain branching predominates chain cleavage [37].

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