Ab initio molecular dynamics of highly charged fullerene cations in intense near-infrared laser fields

Abstract

We theoretically investigated the stability of highly charged fullerene cations produced with an ultrashort intense nearinfrared (IR) laser pulse (light intensity I~ 5 × 10 14 W/cm 2 and wavelength λ ~ 1800 nm). The effects of nonlinear interactions with near-IR pulses are taken into account by combining an ab initio molecular dynamics method with an time-dependent adiabatic state approach. The results indicate that large-amplitude vibration with energy of > 10 eV is induced by impulsive Raman excitation in the delocalized h g (1)-like mode of C 60 z+ . The field-induced large-amplitude vibration of the h g (1) mode persists for a rather long period. In conclusion, C 60 and its cations created upon ionization are extremely robust against field-induced structural deformation. We found that the acquired vibrational energy is maximized at T p ~ vib /2, where T p is the pulse length and T vib is the vibrational period of the h g (1) mode. We confirmed that the vibrational energy deposited in C 60 can be controlled by a pulse train, i.e., by changing the intervals between pulses. Vibrational mode selectivity is also achieved by adjusting the pulse intervals.