Optical properties of charge transfer salts of tetracyanoquinodimethane (TCNQ)

A unified interpretation is given for the infrared and optical spectra of many TCNQ compounds which exhibit a wide variety of physical properties. Inter- and intra-molecular transitions are distinguished by polarization measurements on single crystals of several TCNQ salts. It is suggested that there is incomplete charge transfers in both tetrathiofulvalinium (TTF)- and N-methylphenazinium (NMP)-TCNQ and that the electron-electron interactions are not appreciably screened by the excitonic polarizability of the cations. © 1993.