Atomistic simulation of radiation damage toC60

The threshold displacement energy of buckminsterfullerene C$_{60}$ and formation of the endohedral defect fullerene He@C$_{59}$

“…As our MD simulations give a somewhat higher threshold energy than the measurements we find a correspondingly higher threshold displacement energy T MD d = 26.5 ± 0.8 eV, which is slightly lower than previous simulationbased results [13].…”

“…As seen in Figure 5, this simple model accurately reproduces both the experimental and MD cross sections above E th . There is some (barely significant) deviation close to threshold, which probably due to the fact that T d is not single-valued, but rather varies somewhat with respect to the angles between the imparted momentum and the molecular bonds [13,14], as well as with the stretching of the bonds due to molecular vibrations [15]. The threshold energy E th is projectile dependent [12]; to obtain the intrinsic threshold displacement energy T d we need the energy transferred from the projectile (He) to the target at threshold, which we extract from our MD simulations.…”

“…The threshold displacement energy is distinct from related quantities such as the dissociation energy or the vacancy energy in that it includes the energy barrier between the parent and product states. While independent of projectile, T d depends somewhat on the angle between the momentum imparted to the primary knock-on atom and the inter-atomic bonds [13,14]. Nevertheless, typical values of T d are widely used to model radiation damage across wide ranges of energy.…”

“…With all atoms equivalent, C 60 is the ideal prototype for displacement studies of molecules. Previously reported values of T d for C 60 from electron microscopy experiments and from Molecular Dynamics simulations have spanned a wide range from 7.6-15.7 eV [18] and 29.1 eV [13], respectively. Models of radiation damage to fullerenes have generally assumed a value in the middle of this range, around 15 eV, equivalent to the vacancy energy [19,20,2].…”

Gate Effect of Vacancy-type Defect of Fullerene Cages on Metal-Atom Migrations in Metallofullerenes

“…Irradiation effects on carbon materials with sp 2 bonding structures, such as graphite, fullerenes, and carbon nanotubes, cause new intriguing phenomena . When the carbon materials are irradiated with energy particles, defects (vacancies and interstitial atoms) are formed by knocking carbon atoms from their original positions.…”