title: Orientational changes of supported chiral 2,2'-dihydroxy-1,1'binaphthyl molecules.
abstract: Well defined thin molecular films of 2,2'-dihydroxy-1,1'binaphthyl (binol) molecules at coverages between 5 × 10(15) molecules per cm(2) and 10(17) molecules per cm(2) on thin glass (BK7) substrates were investigated under ultra-high-vacuum (UHV) conditions. Second-Harmonic-Generation Optical-Rotatory-Dispersion measurements (SHG-ORD) were performed using a dedicated spectroscopic setup which allows for the determination of the rotation angle of the SH-signal of two enantiomers. Rotation angles of up to 38 degrees were measured. The chirality of the two enantiomers has been studied at 674 nm (337 nm resonance wavelength) in the transmission mode. Coverage dependent orientation evolution of binol molecular films was revealed by precise monitoring of the surface coverage while performing SHG-ORD experiments. We show that the molecules reach their final orientation at a surface coverage of 5 × 10(16) molecules per cm(2). From the obtained experimental data the ratio of chiral and achiral susceptibility components could be calculated and was observed to change with coverage.
authors.affiliation: Lehrstuhl für physikalische Chemie & Catalysis Research Center, Chemistry Department, Technische Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany. ulrich.heiz@mytum.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Heister
authors.forename: Tobias
authors.initials: T
authors.lastname: Lünskens
authors.forename: Martin
authors.initials: M
authors.lastname: Thämer
authors.forename: Aras
authors.initials: A
authors.lastname: Kartouzian
authors.forename: Sabine
authors.initials: S
authors.lastname: Gerlach
authors.forename: Thierry
authors.initials: T
authors.lastname: Verbiest
authors.forename: Ueli
authors.initials: U
authors.lastname: Heiz