title: Formation and decay of a compressed phase of 4,4'-biphenyldicarboxylic acid on Cu(001).
abstract: The molecular arrangement of 4,4'-biphenyldicarboxylic acid (BDA) on Cu(001) has been studied at high coverage and relatively high temperature (~400 K) using Low Energy Electron Microscopy, LEEM, and selected area diffraction, μLEED. Next to the previously reported c(8 × 8) structure, we also observe a compressed phase with a [structure: see text] superstructure in matrix notation. All four equivalent (rotational and mirror) domains are equally populated. Both the c(8 × 8) and the compressed phase are confined to the first layer and the latter has a 14% higher density compared to the c(8 × 8) phase. Remarkably, this compressed phase is stable only during deposition and decays after interruption of the deposition. Apparently, the density of physisorbed admolecules on top of the c(8 × 8) layer has to be above a relevant threshold to allow the formation of the compressed phase.
authors: Physics of Interfaces and Nanomaterials, MESA + Institute for Nanotechnology, University of Twente, Enschede, Netherlands.
authors: Daniel
authors: D
authors: Schwarz
authors: Raoul
authors: R
authors: van Gastel
authors: Harold J W
authors: HJ
authors: Zandvliet
authors: Bene
authors: B
authors: Poelsema
mesh_terms: D001713:Biphenyl Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003998:Dicarboxylic Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D013499:Surface Properties; D013696:Temperature
chemical_list: C535263:4,4'-biphenyldicarboxylic acid; D001713:Biphenyl Compounds; D003998:Dicarboxylic Acids; D003300:Copper