Analytical Potential Functions Based on Force-Fields for　Studying the Dynamics of Vibrationally Excited and　Reactive Carbon Nanotubes Interacting with Aminoacids

摘要

Analytical potential functions based on force-fields usually employed in Molecular Dynamics simulations　are constructed for studying vibrationally excited and reactive carbon nanotubes interacting　with aminoacids. The proposed method is illustrated by producing an all-atom potential energy surface　of a (5, 5)-capped carbon nanotube with a N-centered glycine radical. It is demonstrated that　by parametrizing separately the short and long range carbon-nitrogen interactions and interpolating　them by proper switching functions we can construct an analytical potential which fits calculated　density functional theory points along the reaction path described by the (C_(tube)-N_(glycine)) bond.　Vibrational spectra obtained from classical mechanical trajectories reveal regular localized motions　for excitation energies below the barrier of dissociation. Regularity of the motions is further confirmed　by locating families of stable periodic orbits. These results validate the use of (semi)classical　mechanics and encourage the investigation of larger nanotubes.