Structure and composition of adsorbed layers formed by sequential exposure of Pt(100) and Pt(111) to pairs of compounds: Solvents and electrolytic substances

Atomic Resolution Imaging of Adsorbates on Metal Surfaces in Air: Iodine Adsorption on Pt(111)

“…Additional tunneling spectroscopic experiments and theoretical calculations of the local electronic structure are required to confirm this interpretation of the (V7' x F7)R19.10 images. At an iodine coverage of 0.44, the iodine is expected to form a (3 x 3) unit cell (18)(19)(20). We found that, by cooling the annealed Pt crystal only 2 mm from the iodine crystals in the dosing cell, the surface was predominately covered by (…”

“…Dosing of Pt(111) with iodine in UHV leads to the formation of two possible unit cells (16,17), (V3 x V3-), 01 = 0.33 (structure 1), and (V7 x V7'), 0I = 0.43 (structure 2). Adsorption of iodine from a 10-3M KI solution leads to the formation of (3 x 3), 01 = 0.44 unit cell (structure 3) (18). Indirect evidence from electrochemical characterization indicates that it is possible to form both structures 2 and 3 by annealing the surface in a H2 flame and cooling it in a I2-N2 carrier gas stream (19).…”

Detailed characterization of (3×3) iodine adlayer on Pt(111) by unequal-sphere packing model

“…This lattice has been reported and described as ͑3 ϫ 3͒-asym. In the STM image, [14][15][16] it is easily recognizable due to a specific image pattern with one atom down ͑in the hollow site͒ and its neighbors in so-called "asymmetric" sites, 7 which from our plot are equal to 2.432 NAH units. Corrugation or the adlayer thickness of the iodine ͑3 ϫ 3͒-asym is 0.215 NAH units, which is 0.006 units bigger than that for ͑3 ϫ 3͒-sym adlayer.…”

“…These lattices have been characterized by LEED, [6][7][8][9][10][11][12] ADAM, 13 STM, [14][15][16] and Surface X-ray Scattering ͑SXS͒. [17][18][19][20][21] The same type of iodine adlayer on Pt͑111͒ was found for preparations from gas phase [12][13][14] and from aqueous solution.…”

“…[17][18][19][20][21] The same type of iodine adlayer on Pt͑111͒ was found for preparations from gas phase [12][13][14] and from aqueous solution. [6][7][8][9][10][11]15,16 Experimental data also show that an iodine adlayer with ͑3 ϫ 3͒ unit cell structure can form two distinct lattices, 10,[13][14][15][16] in which iodine-iodine interatomic distance ͑4.162 Å͒ and surface coverage are the same, but iodine adatoms possess different registries. They are known as the ͑3 ϫ 3͒-sym and ͑3 ϫ 3͒-asym adlattices.…”