Multimorphism in molecular monolayers: Pentacene on Cu(110)

Monolayer and bilayer pentacene on Cu(111)

“…Chemisorption between the first layer and the Cu substrate involves distortion of the molecules, as found in theory work on Cu(110) 17 . For molecules adsorbed flat on the surface and imaged with a bias voltage either below the highest occupied molecular orbital (HOMO) or above the lowest unoccupied molecular orbital (LUMO), the shape of the orbitals will affect the apparent shape of the molecules in STM.…”

“…While deposition on inert surfaces such as SiO 2 or Bi/Si(111)-7×7 leads to a similar but not identical structure with the molecular axes nearly perpendicular to the substrate surface 7,8 , deposition on metallic surfaces such as Au, Cu or Ag result in adsorption with the molecular plane parallel to the surface. On Au 9-13 and Ag [14][15][16] the molecule appears flat; however, on Cu surfaces the molecule acquires a bending that is clear in scanning tunneling microscopy (STM) [17][18][19][20][21][22] and atomic force microscopy (AFM) 23 measurements and has been quantified using DFT for adsorption on Cu(110) 17 on Cu(110) is approximately 0.04 nm measured between the center of the molecule and a plane bisecting the H atoms at either end and is shown in Figure 1 (c). Adsorption on Cu(111) has also been studied using DFT, though during relaxation the C atoms were constrained to be parallel to the surface, so molecular bending could not be reproduced 24 .…”

Coverage-dependent structural phase transformations in the adsorption of pentacene on an aperiodically modulated Cu film

“…33 The bending of an isolated Pn molecule has also been quantified using DFT. 6,8,9,32 The bending on the Cu(001) surface is approximately 0.4 Å measured between the center of the molecule and a plane bisecting the H atoms at either ends, 10 and on Cu(100) and Cu(111) surfaces, the values are 0.16 Å and 0.2 Å measured between the center of the molecule and a plane bisecting the C atoms at either ends. 8,9 Al(001) shows a larger value for bending with peculiar V-shape, where the height di↵erence between the peripheral and central carbon atoms is 1.24 Å.…”

“…Bending of Pn molecule. On low Miller index Cu planes, the Pn molecule experiences a bending that can clearly be seen with STM 8,10,11,[30][31][32] and atomic force microscopy (AFM). 33 The bending of an isolated Pn molecule has also been quantified using DFT.…”

“…Significant deviation from a conventional planar adsorption configuration has been reported for Au(110), with mixed edge on/planar phases 5 and for Al(001), with a peculiar V-shaped bending. 6 Otherwise, a minor symmetrical bending of the molecule with the central ring closer to the surface has been reported for adsorption on Au(111), 7 Cu(001), 8 Cu(111), 9 and Cu(110) 10 surfaces. The adsorption site on Cu(111) at low temperature was revealed by Lagoute et al 11 using scanning tunnelling microscopy (STM).…”