The investigations of low frequency oscillation spectra of selected charge transfer molecular complexes and their compounds by inelastic thermal neutron spectroscopy

Dynamical properties, in particular in the low frequency range, of charge transfer complexes (CT), in which the molecules of tetracyanoquinodimethane, tetracyanoethylene, 2,5-dihydroxy-3,6-dichloro-1,4-benzoquinone, and 2,3,5,6- tetracyanobenzene act as charge acceptors, and the molecules of hexamethylbenzene and 2,3,5,6-tetramethylpyrazine - as charge donors are described. Dynamical properties of separate components of these complexes were also studied. The spectroscopy of inelastically scattered neutrons (INS) in particularly suitable for studies of molecular vibrations in low frequency range. The INS method is complementary to the classical optical spectroscopy techniques (IR and Raman) and finds today broad use in molecular spectroscopy studies. Its feature is the lack of selection rules due to the symmetry of the molecule and dominant role of hydrogen nuclei vibrations in neutron scattering process. Theoretical foundations of thermal neutron scattering and their interactions with matter, neutron sources and spectrometers are described. The applications of INS method in molecular spectroscopy studies of biologically active compounds, high symmetry compounds and systems with strong hydrogen bonds are also reviewed. (author)