Dielectric constants of C60 and C70 thin films

Transmittance and reflectance spectra of C-60 and C-70 thin films have been measured at room temperature from 1.5 to 6.0 eV for 45 degrees incidence with s-polarized light. The most reliable dielectric constants are obtained by fitting the observed optical values to the calculated ones using a strict solution of Maxwell equations. The imaginary part of the molecular polarizability spectrum was converted from the dielectric constants using Clausius-Mossotti's formula. For C-60, the spectrum shows good correspondence, in peak positions and intensities to that of solution in hexane, except for the structure from 2.3 to 3.0 eV die to the intrinsic solid state effect. The same correspondence is also observed in C-70, but no apparent solid state effect is observed. (C) 1997 Elsevier Science Ltd.