title: Resonant x-ray reflectivity from a bromine-labeled fatty acid Langmuir monolayer.
abstract: Resonant x-ray reflectivity exploits the energy dependence of atomic scattering factors to locate resonant atoms within the electron density distribution of thin films. We apply the technique to a monolayer of bromo-stearic acid at the air/water interface. The data collection protocol employed cycles through several energies in the vicinity of the bromine K absorption edge and verifies that the energy dependencies observed are indeed resonant effects. The analysis specifies the location of the Br atom with sub-angstrom precision and must consider both the real and imaginary parts of the changes in the scattering factor to be consistent with the known structure and stoichiometry of this test case.
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA. strzalka@sas.upenn.edu
authors.forename: Joseph
authors.initials: J
authors.lastname: Strzalka
authors.forename: Elaine
authors.initials: E
authors.lastname: DiMasi
authors.forename: Ivan
authors.initials: I
authors.lastname: Kuzmenko
authors.forename: Thomas
authors.initials: T
authors.lastname: Gog
authors.forename: J Kent
authors.initials: JK
authors.lastname: Blasie
mesh_terms: D000465:Algorithms; D001966:Bromine / Q000032:analysis* / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D008567:Membranes, Artificial; D013229:Stearic Acids / Q000032:analysis* / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D005227:Fatty Acids; D008567:Membranes, Artificial; D013229:Stearic Acids; C031183:stearic acid; D001966:Bromine