Theoretical Investigation On Interactions Of Fast Ions With Double-walled Carbon Nanotubes

Interactions of fast ions with double-walled carbon nanotubes have been studied theoretically in this paper. A semi-classical kinetic model combined with the dielectric response theory is employed to study the electronic excitation on the nanotube walls during the channeling of fast ions through double-walled carbon nanotubes. Our analytical expressions of the induced electron density, induced potential, self-energy, stopping power, radial total potential and radial total force are obtained with a proton moving parallelly to the axis of the double-walled carbon nanotubes.It is found that the induced electron density is influenced by the proton velocity when a proton moving along the axis of the double-walled carbon nanotubes. And we also find that the induced electron density presents two different kinds of trends for high and low proton velocity. Moreover, the induced electron density has a wake-like oscillation effects when the proton speed is above the threshold speed, at about v= 0.6a.u.. Besides, the calculation results show us interesting double-peak curves of the self-energy and stopping power, under strong influence of the damping factor and the special double-walled nanotube geometry. With the increase of the damping factor, we can observe that both of the self-energy and the stopping power keep decreasing in magnitude. Moreover, relatively increasing the chiral parameter of the outer wall can reduce the interference effects between the two walls and weaken the double-peak to one-peak shapes. Finally, we can see that the maximums of potential wall are about at the position of (?) and (?).