Adsorption of a Hydrogen Atom on a Graphene Flake Examined with Quantum Trajectory/Electronic Structure Dynamics

Adsorption of atomic hydrogen colliding with C37H15, a planar "flake" of graphene, is examined using a hybrid quantum trajectory/electronic structure (QTES) dynamics for the values of the collision energies below 2.0 eV. The entire system of 53 atoms is represented by a quantum trajectory ensemble. The quantum correction on dynamics is included for the adsorbing hydrogen. The electronic structure is computed on-the-fly using the density functional tight binding (DFTB) method. The highest probability of adsorption is obtained for the kinetic energy of incident hydrogen in the range from 0.1 to 0.9 eV. Adsorption mechanism involves transfer of the collision energy to the graphene flake and projection of the carbon atom of the forming CH bond, accompanying sp(3) hybridization of orbitals. The QTES DFTB simulations with and without the quantum correction show that localization of the proton wave function and details of the mixed quantum/classical description of light and heavy nuclei greatly influence the adsorption probabilities.