Application of THz Spectroscopy in Molecular Crystals

On the basis of the quantitative analyses of the nature of THz modes in a series of prototype molecular crystals, we use a single-value
$G$
factor in order to measure the extent to which the intermolecular and intramolecular vibrations mix with each other in any molecule system of interest. We propose to use the
$G$
factor as a global value for characterizing the nature of THz modes of molecular crystals. By comparing the configuration of any molecule of interest with the configurations of the prototype molecules, one can estimate the location of his molecule on the
$G$
scale and thus, make a qualitative assignment for the THz modes in terms of the mixing between intermolecular and intramolecular vibrations.