Unrestricted study of the Eley–Rideal formation of H2 on graphene using a new multidimensional graphene–H–H potential: role of the substrate

Abstract

The Brenner potential is adapted to handle chemical interactions and reactions of H atoms at a graphene surface. The adapted potential reproduces several important features of DFT computed data and reveals an extended puckering of the surface upon its adsorption of an H atom. This potential is used to investigate in a much more realistic way than has been done before, the Eley-Rideal abstraction reaction producing H(2) in H + H-graphene collisions at energies E(col)< or = 0.2 eV. The graphene surface is represented by a slab of 200 carbon atoms and the study is carried out using classical molecular dynamics for vertical incidences in a cylinder centered about the chemisorption axis. A highlight of the present study is that upon the arrival of the gas phase H atom, the adsorbent C atom is attracted and pulls out its surrounding surface atoms. The hillock thus formed remains puckered until the newly formed molecule is released. The range of impact parameters leading to reaction depends on the collision energy and is governed by the shape of the entrance channel potential; the reaction probability in this range is 100%. On average, in the studied E(col) range, the available energy (3.92 eV + E(col)) is shared as: 69-52% for the internal energy, 11-23% for the translation energy and 20-25% for the energy imparted to the surface. Also, the average vibration and rotation energy levels of the nascent H(2) molecule are, respectively, v = 5-4 and j = 2-4.

Interstellar H adsorption and H2formation on the crystalline (010) forsterite surface: a B3LYP-D2* periodic study

“…coronene clusters and C(0001) surfaces) have been published, [12][13][14][15] generally predicting a high reaction probability and significant ro-vibration populations in nascent molecules, in agreement with the experimental findings. 16 Usually, effects due to the presence of porous and point defects were not accounted for.…”

KINETIC MONTE CARLO STUDIES OF H2FORMATION ON GRAIN SURFACES OVER A WIDE TEMPERATURE RANGE

“…It should be noted, however, that experiments and calculations indicate that H atoms can chemisorb onto graphite and graphene only after surmounting a barrier of 0.2 eV (Jeloaica & Sidis 1999;Bachellerie et al 2009;Ivanovskaya et al 2010). Nevertheless, we consider a model for barrierless chemisorption in which only chemisorption sites are available, based on Models O1 and O2.…”

Dynamics of H2 Eley-Rideal abstraction from W(110): Sensitivity to the representation of the molecule-surface potential

“…[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Results of classical trajectory calculations have been found in reasonable agreement with those of quantum scattering simulations for ER abstraction involving hydrogen atoms in reduced dimension models. 12,13,20,23,[25][26][27][28][29][30][31][32][33][34][35][36] Early dynamical studies of the H+H/W ER process made use of twodimensional (2D) model potential energy surfaces (PES), depending on the altitude of the molecule above the surface and the H-H distance, representing only a collinear geometry where the projectile impinges on top of the target atom. 11,37 More recently, Rutigliano and Cacciatore 38 investigated the ER abstraction process for H+H/W(100) by using a tight binding approximation for the PES 39,40 that allowed them to consider explicitly not only the six degrees of freedom of the H 2 but also the dynamical coupling with tungsten phonons.…”