DOI: 10.1051/jp2:1993165
J. Phys. II France 3 (1993) 761-766

Surface diffraction studies of 2D crystals of short fatty alcohols at the air-water interface

A. Renault¹, J.F. Legrand², M. Goldmann³ and B. Berge<sup>1

1</sup>  Laboratoire de Spectrométrie Physique, URA08, Université J. Fourier, B.P. 87, 38402 Saint Martin d'Hères, France
²  European Synchrotron Radiation Facilities, B.P. 220, 38043 Grenoble, France
³  PSI, Institut Curie, 11 rue P. et M. Curie, 75005 Paris, France

(Received 9 April 1993, accepted 27 April 1993)

Abstract
Using X ray surface diffraction we have investigated crystalline monolayers of short alcohols (1-decanol to 1-tetradecanol) at the air-water interface in the vicinity of the first order transition corresponding to 2D melting ( (2D)). The diffraction patterns in the solid phase are in agreement with a 2D hexagonal close-packing. The lattice parameter value is 5.00 Å just below (2D) and amounts 4.90 Å at  K. The resolution limited Bragg peaks indicate a large crystalline coherence length. At the approach of the 2D melting point, the observed increase of the Debye Waller factor is attributed to critical fluctuations.

PACS
68.00 - 68.42

© Les Editions de Physique 1993