title: Langmuir films of chiral molecules on mercury.
abstract: Homo- and heterochiral Langmuir films of a chiral derivative of stearic acid are studied in situ on the surface of liquid mercury as a function of surface coverage by surface tensiometry and surface-specific synchrotron X-ray diffraction and reflectivity. A transition from a phase of surface-parallel molecules to a phase of standing-up molecules is found. The former shows no surface-parallel long-range order. The standing-up phase of both homochiral and heterochiral compositions exhibit long-range order. However, the former has an oblique unit cell with parallel molecular planes, and the later has a centered rectangular unit cell with a herringbone molecular packing. For both cases, the standing-up molecules are tilted by 44 degrees from the surface normal and pack at a density of 19.5 A(2)/molecule in the plane normal to the molecular long axis. Important differences are found, and discussed, between this behavior and that of a Langmuir film of the nonchiral stearic acid on mercury.
authors.affiliation: Physics Department, Bar-Ilan University, Ramat-Gan 52900, Israel.
authors.forename: L
authors.initials: L
authors.lastname: Tamam
authors.forename: T
authors.initials: T
authors.lastname: Menahem
authors.forename: Y
authors.initials: Y
authors.lastname: Mastai
authors.forename: E
authors.initials: E
authors.lastname: Sloutskin
authors.forename: S
authors.initials: S
authors.lastname: Yefet
authors.forename: M
authors.initials: M
authors.lastname: Deutsch