Ab initio molecular dynamics and wavepacket dynamics of highly charged fullerene cations produced with intense near-infrared laser pulses

We theoretically investigated the stability of highly charged C-60(2+) cations produced with an ultrashort intense laser pulse of lambda similar to 1800 nm. We first review the results of our theoretical investigation of the stability of C-60(2+) cations and report that C-60(2+) cations up to z = 12 can be produced as a stable or quasistable (mu s-order lifetime) intact parent cation. We next present the results of simulation as to how much vibrational energy is acquired by C-60 or C-60(z+) through the interaction with an ultrashort intense pulse of 60 A = 1800 run. This type of simulation was carried out by incorporating an ab initio classical molecular dynamics method into the framework of the time-dependent adiabatic state approach. The results indicate that large-amplitude vibration with energy of > 20 eV is induced in the h(g)(l) mode of C60. C60 or 06, is mostly elongated along the field polarization direction, of which the motion can be described by using the time-dependent (TD) potential along the hg(l) coordinate. We also solved the corresponding TD Schrodinger equation to propagate the vibrational wavepacket on the TD potential. We found that the acquired vibrational energy is maximized at T-p similar to T-vib/2, where Tp is the pulse length and T-vib is the vibrational period of the h,(I) mode. We show how the vibrational energy deposited in C60 can be controlled by changing the pulse separation of a train of three pulses. We finally discuss the structure and dissociation of C-60(2+) . (c) 2007 Elsevier B.V. All rights reserved.