Regensburg 2002 – scientific programme

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O: Oberflächenphysik

O 13: Postersitzung (Adsorption an Oberfl
ächen, Elektronische Struktur, Magnetismus in reduzierten Dimensionen, Epitaxie und Wachstum, Halbleiteroberfl
ächen und -grenzfl
ächen, Organische Dünnschichten)

O 13.12: Poster

Monday, March 11, 2002, 18:00–21:00, Bereich C

ESTABLISHING THE KINETICS OPTICAL PARAMETERS OF THE ORGANIC THIN FILMS — •Radu Todoran and Daniela Todoran — North University of Baia Mare, Romania

The paper present the determinations of some kinetic parameters that characterize the kinetics of the adsorption phenomenon of some organic xanthate molecule on the surface of some natural semiconductor mineral (galena, sphalerit) in order to understand the inward mechanism of this phenomenon. Among the methods of inquiry that allow kinetics determination in situ the optical ones were chosen relying on the change of the relative reflection of the liquid-mineral semiconductor interface, and permitting continuous inquires without disturbing the inward development of the processes. Into the computation, we took into the consideration the physical values which feature the roughness of the solid surface, the diffusion into liquid media and the energetic non-homegeneities of the surface. The Rs/Rp = f(q) characteristic helps us to establish the thickness of the adsorbed layer, as well as to determine the optical parameters of the thin film. Using the Kramers-Kronig formalism and with the aid of optical reflection spectra UV-VIS, we could calculate the following optical functions for the adsorption layers: the optical adsorption coefficient a; the refraction index n; the adsorption index k; the effective valence number nef; the real part e1 of the dielectric constant; the imaginary part e2 of the dielectric constant; the functions of the characteristic losses of the electrons -Ime-1 and -Im(1+e)-1; the effective dielectric constant eef ; the function e2E2.