Isotopic mass effects for low-energy ion channeling in single-wall carbon nanotubes

Monte Carlo (MC) simulation studies of isotopic mass effects have been conducted, for low-energy channeling of C-12 and C-13 ions in single-wall carbon nanotubes. It is found in MC simulations that (Psi(C) (for) C-12/Psi(C) (for) C-13) = (13/12)(1/2), for the same incident energies. Here, Psi(C) (for) C-12 is the critical angle for C-12 channeling, and Psi(C) (for) C-13 is the critical angle for C-13 channeling. This work shows the mass effect to be the incident momentum one, but a recent work (Moura, C. S.; Amaral, L. J. Phys. Chem. B 2005, 109, 13515) considered it to be the energy transfer effect. Our work disagrees with that of Moura and Amaral.