Self-Atomic Motions of Protons

To date, incoherent quasi-elastic neutron scattering experiments on the a-relaxation regime of glass-forming polymers have revealed the following main features for the self-motion of hydrogens  

It is characterized by an effective mean squared displacement of the proton From such studies it was found [148] that the Q-dependence of r eif can approximately be described by a power law determined by the stretching exponent (3  

Though the BS experiments have been very useful for gaining insight into the hydrogen motions taking place during a-relaxation, they are affected by a number of shortcomings  

Due to the convolution with the instrumental resolution, an accurate determination of the spectral shape is not possible. Therefore, the value of has to be determined by other methods or from coherent scattering measurements. 

The energy or time resolution is worse than that of NSE. 

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