Simultaneous determination of the thickness and the dispersion of the dielectric constant of a Langmuir-Blodgett film deposited on a CaF2 plate

A procedure for simultaneous determination of the thickness and the optical dielectric constant of a thin organic film on a transparent substrate has been proposed. With this procedure these physical quantities can be determined from data collected by a conventional ultraviolet-visible spectrometer without depending on any dispersion model of the organic film. The thickness and the dielectric constant (in the wave number range of 3.6×104-1.2×104 cm−1) have been determined for 25-layer and 37-layer Langmuir-Blodgett films of a calcium arachidate-arachidic acid mixture. The results for these films agree with each other, showing the utility of the proposed procedure.