DETERMINATION OF THE OPTICAL-CONSTANTS OF A UNIAXIAL ULTRATHIN-FILM FROM FT-IR SPECTROSCOPY

To evaluate the optical anisotropy of ultrathin films (d <400 Angstrom ), we have developed two calculation procedures which permit us to obt ain the complex refractive indexes (n) over tilde(o) and (n) over tild e(e) directly From experimental FT-IR spectra. In the first procedure, two transmission spectra recorded at different angles of incidence ar e used. The second one requires a transmission spectrum al normal inci dence and a normalized differential reflection spectrum (PM-IR-RAS) at grazing incidence. In the present work, these methods have been appli ed to Langmuir-Blodgett cadmium arachidate monolayers in order to illu strate their possibilities.