The interaction of Li atoms with a graphene monoxide (GmO) monolayer in various Li x C y O y structures is investigated to determine if a monolayer of GmO can bind Li atoms and to predict the maximum theoretical capacity of this potentially new anode material for Li-ion batteries. Density functional calculations show that Li atoms are adsorbed on the GmO monolayer by attaching to the oxygen atoms and that Li atoms tend to repel during lithiation. An isolated Li atom prefers adsorption at the hollow site of the carbon sublattice although the hollow site of the oxygen sublattice, which is close in energy, may be preferable for multilayer systems since it allows Li atoms to move closer to the monolayer; at higher Li concentrations, the Li 2 C 6 O 6 configuration for monolayer GmO is energetically stable while an equivalent configuration for graphene (Li 2 C 6 ) is not, and Li 2 C 2 O 2 (with a theoretical capacity of 957 mAh/g) has a formation energy near zero. Analysis of the band structure and density of states shows that Li donates a large fraction of its valence electron to the GmO although there is also the formation of covalent Li−O bonds, thus facilitating the formation of Li + ions when leaving the GmO monolayer. These characteristics are desirable for the battery anode material and suggest that GmO, especially in the multilayer form, is a promising candidate.

The ion cloud produced from residual gas in an electron accelerator can degrade machine performances and produce instabilities. The ion dynamics in an accelerator is governed by the beam-ion interaction, magnetic fields and eventual mitigation strategies. Due to the fact that the beam has a nonuniform transverse size along its orbit, the ions move longitudinally and accumulate naturally at some points in the accelerator. In order to design effective mitigation strategies it is necessary to understand the ion dynamics not only in the transverse plane but also in the longitudinal direction. After introducing the physics behind the beam-ion interaction, we show how to get accumulation points for a realistic electron storage ring lattice. Simulations of the ion cloud dynamics, including the effect of magnetic fields on the ions, clearing electrodes and clearing gaps are shown. Longitudinal ion trapping due to the magnetic mirror effect in the dipole fringe fields is also detailed. Finally, the effectiveness of clearing electrode using longitudinal clearing fields is discussed and compared to clearing electrodes producing transverse field only.