Inelastic resolution

Specimens for (S)TEM have to be transparent to the electron beam. In order to get good contrast and resolution, they have to be thin enough to minimize inelastic scattering. The required thin sections of organic materials can be obtained by ultramicrotomy eitlier after embedding into suitable resms (mostly epoxy- or methacrylate resins [H]) or directly at low temperatures by cryo-ultramicrotomy [12]. 

The other technique is HREELS (high resolution EELS) which utilises the inelastic scattering of low energy electrons in order to measure vibrational spectra of surface species. The use of low energy electrons ensures that it is a surface specific technique, and is often chosen for the study of most adsorbates on single crystal substrates. 

The width of the peaks in LETS depends upon the sharpness of the onset of the inelastic process, which in turn depends upon the thermal distribution of electron energies about EP. Thus, the IETS line width depends strongly on temperature and as shown by (3) [75]. Because of this, vibrational IETS provides infrared-quality resolution only when performed below 5 K. Electronic transitions are usually much broader than vibrational transitions therefore, electronic IETS is usually performed at liquid nitrogen temperature and slightly above (>77 K). An example of a system showing both vibrational and electronic IETS is presented in Fig. 5 [19]. 

Seman TR, Mallik RR (1999) Electronic signal regulator for constant resolution inelastic electron tunneling spectroscopy. Rev Sci Instrum 70 2808-2814... 

Tetramethylplumbane mixtures with tetramethylstannane were studied at 2 K by high resolution INS (inelastic neutron scattering), revealing rotational tunnelling transitions for the methyl groups146. 

While a high-resolution inelastic neutron scattering study has attempted... 

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