A hydrogen atom can either physisorb or chemisorb onto a graphene surface. To describe the interaction of H with graphene, we trained the C-C, H-H, and C-H interactions of the ReaxFF CHO bond order potential to reproduce Density Functional Theory (DFT) generated values of graphene cohesive energy and lattice constant, H dissociation energy, H on graphene adsorption potentials, and H formation on graphene using the Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) processes. The results, generated from the trained H-graphene potentials, are in close agreement with the corresponding results from DFT. The advantage of using optimized CH potentials is, for example, the inclusion of physisorption interactions and quantum mechanical features of chemical bonding in the functional forms of the potentials. The trained CH potentials are utilized to study the energetics of formation of an H molecule on graphene using the Eley-Rideal and Langmuir-Hinshelwood processes. Potential energy surfaces for the formation of H through ER are generated for the collinear and oblique approach of the second hydrogen atom. Energetics of the formation of H through LH is studied for a variety of cases such as when hydrogen atoms are chemisorbed or physisorbed and when hydrogen occupies ortho, meta, or para chemisorption sites. The likelihood of H formation through LH for various configurations is discussed. Furthermore, the tunneling probability of an atom through a continuous symmetric/asymmetric barrier is calculated and applied to an adsorbed hydrogen atom on graphene.

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The impact of interfacial transition layer thickness Δ is methodically investigated in the (BeSe)10–Δ/(Be0.5Zn0.5Se)Δ/(ZnSe)10–Δ/(Be0.5Zn0.5Se)Δ superlattices (SLs) for comprehending their phonon dispersions, Raman intensity profiles, and atomic displacements. By varying Δ from one to three monolayers, we have noticed a dramatic increase in the Raman intensity peaks with slight upward shifts of ZnSe-related optical phonons. An insignificant change is perceived, however, in the Raman features with remarkable downward shifts of the BeSe-type confined optical modes. These effects are ascribed to the localization of atomic displacements at the interfacial regions. The variations in phonon frequencies and enhancement of Raman line shapes can be used as vital tools for establishing the interfacial structures in SLs of technological importance.