Using helium(-3) atom scattering, we have studied the adsorption kinetics, the structure and the diffusional dynamics of atomic hydrogen on the surface of a graphene monolayer on Ni(111). Diffraction measurements reveal a 4 degrees rotated rectangular hydrogen overstructure. Hydrogen adsorption and desorption exhibit activation barriers of E-a = (89 +/- 7) meV and E-d = (1.8 +/- 0.2) eV, respectively. Helium(-3) spin-echo measurements showed no decay of the spatial correlation function (or intermediate scattering function) within the time range of the spectrometer. Hence, we are able to set lower limits for a possible hydrogen surface diffusion rate. (C) 2016 Elsevier Ltd. All rights reserved.
机构:
Islamic Azad Univ, Cent Tehran Branch IAUCTB, Dept Phys, Tehran, IranIslamic Azad Univ, Cent Tehran Branch IAUCTB, Dept Phys, Tehran, Iran
Shavikloo, Masoumeh
Kimiagar, Salimeh
论文数: 0引用数: 0
h-index: 0
机构:
Islamic Azad Univ, Cent Tehran Branch IAUCTB, Dept Phys, Nano Res Lab, Tehran, IranIslamic Azad Univ, Cent Tehran Branch IAUCTB, Dept Phys, Tehran, Iran