J. Phys. I France
Volume 6, Number 7, July 1996
Page(s) 891 - 906
DOI: 10.1051/jp1:1996105
J. Phys. I France 6 (1996) 891-906

X-ray Scattering Study of the Melting Transition of a CCl $\mathsf{_4}$ Monolayer on Graphite

P. 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, $\eta Q_{\rm B}$, 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 $\eta Q_{\rm B}$ 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 $\eta Q_{\rm B}$ and coherence length which are in agreement with theoretical predictions in both solid and liquid regimes.

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