Controlling desorption of H, O, atoms and OH group from graphene by pulse laser

Possibilities of reduction of graphene oxide and one-side dehydrogenation of graphane (H-terminated graphene) with using ultra-short pulse ($\sim$2 fs) laser are discussed. We have performed molecular dynamics (MD) simulation of O-, H-, and OH-adsorbed graphene sheets induced by electronic excitation upon irradiation with laser pulse. The time-dependent density functional theory treating real-time propagation of electron wave functions combined with the Ehrenfest approximation for the MD was employed and FPSEID [1] code was used to check the energy conservation rule under dynamical external field [2]. We found asymmetric pulse shape as a function of time causes an efficient desorption of O atoms and OH groups from graphene which can be applicable for reduction of graphene oxide alternative to chemical and thermal treatment. Meanwhile, such asymmetric pulse shape is beneficial for one-side H-desorption from graphane that will trigger further structural changes such as spontaneous shrink/rippling or heterogeneous termination on side-by-side.\\[4pt] [1]O. Sugino, Y. Miyamoto, PRB{\bf 59}, 2579, (1999);B{\bf 66}, 089901(E) (2002)\\[0pt] [2]Y. Miyamoto, H. Zhang, PRB{\bf 77}, 165123 (2008)