Tight-binding molecular dynamics simulations of radiation-induced fragmentation ofC60

Abstract

The fragmentation of the C 60 fullerene was investigated using tight-binding molecular dynamics simulations based on the parametrization of Papaconstantopoulos et al. ͓MRS Symposia Proceedings No. 491 ͑Materials Research Society, Pittsburgh, 1998͒, p. 221͔. Averaged fragment size distributions over random sets of initial configurations were obtained from simulations of radiation-induced fragmentation in the 50-500 eV excitation energy range. The excitation caused by the radiation was simulated simply by ascribing suddenly random velocities to each atom of the fullerene cage. For low excitation energies, the size distributions are peaked for dimers ͑reflecting a preferential C 2 emission͒ and a bimodal size dependence characterizes the distributions of the complementary small and large fragments. For high excitation energies, predominantly multifragmentation occurs, but a genuine power-law dependence of small fragments is not yet observable. A phase transition is found for rather low excitation energies ͑100-120 eV͒.

Ultrafast dynamics and fragmentation of C60 in intense laser pulses

“…The open-cage distortion takes place in the case of short wavelength, and the fragmentation into C 2 dimers or C atoms takes place in long wavelength. The above result is slightly different with the simulation which deals the effect of laser as a sudden heating and obtains a continuous distribution of C n fragments [26,27]. Such difference was also mentioned in Ref.…”

“…Recently, ionization and fragmentation of C 60 fullerenes via the excitation of LUMO+1 state was studied in elliptically polarized intense femtosecond laser field [24,25] to weaken ATI and HHG by reduced electronic recollision. And molecular dynamics (MD) simulations [26,27] were employed to generalize the rules of laser-induced fragmentation of C 60 fullerenes. However, for studying such ultrafast electronic excitation progress, MD simulation is not an appropriate theoretical approach because the motion of C 60 is beyond the Born-Oppenheimer approximation.…”

Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature

“…The first hint that electronic excitations may be important to break the C 60 cage comes from the observation that strong radiation fields lead to charge photo-excitation, ionization and plasmon excitation inducing the fragmentation of buckminsterfullerene. 51,52 In particular, upon high-intensity femtosecond laser excitation, C 60 undergoes a "giant" plasmon resonance at 20 eV. This collective charge excitation leads to an efficient energy transfer to the vibrational modes of the molecule and to a possible rupture of the cage via two-plasmon excitation.…”

Tight-binding vibrational analysis of single-wall carbon nanotubes

“…We have successfully employed the non-orthogonal TB parametrization of Papaconstantopoulos et al over more than a decade in structural and vibrational studies concerning polymers of a variety of fullerenes (C 36 , C 60 , and C 70 ) [14,15], as well as in investigations of the fragmentation of various fullerenes (C 36 , C 60 , C 70 , and C 90 ) [16,17].…”

“…The electronic structure is calculated in the framework of a non-orthogonal tight-binding formalism [14,15,16,17] and the normal mode analysis of the molecular vibrations is carried out based on the eigenvalue problem of the dynamical matrix.…”