J. Phys. I France 6 (1996) 891-906
X-ray Scattering Study of the Melting Transition of a CCl Monolayer on GraphiteP. Aranda1, T. Ceva1, B. Croset1, N. Dupont-Pavlovsky2 and M. Abdelmoula3
1 Groupe de Physique des Solides URA CNRS 17, Universités Paris 6 et Paris 7, Tour 23-13, 2 place Jussieu, 75251 Paris Cedex 05, France
2 Laboratoire de Chimie du Solide Minéral URA CNRS 158, Université Nancy 1, boulevard des Aiguillettes, B.P. 239, 54506 Vandoeuvre les Nancy, France
3 Laboratoire M. Letort, 45 rue de Vandoeuvre, 54600 Villers les Nancy, France
(Received 10 January 1996, received in final form 25 March 1996, accepted 9 April 1996)
We have performed an extensive X-ray scattering study of 0.85 monolayer of carbon tetrachloride adsorbed on graphite with a rotating anode X-ray generator. By using a position sensitive detector, we were able to study simultaneously two diffraction peaks during the whole melting transition. A measure of the Debye-Waller correlation function coefficient, , based on peak broadening was performed for the two peaks in the solid regime. The proportionality law between these two coefficients has been verified, with a fairly good agreement and it confirms the quasi-long-range order in the solid. At melting, the coefficient for the first peak is equal to 0.23, a value compatible with previous experimental work and standard theory. The intensities of the diffraction peaks exhibit variations with and coherence length which are in agreement with theoretical predictions in both solid and liquid regimes.
© Les Editions de Physiques 1996