Anisotropic Coulomb explosion of C60 irradiated with a high-intensity femtosecond laser pulse

Abstract

C 60 vapor was irradiated with an intense femtosecond laser pulse (1×1016 W/cm2 in 120 fs at a wavelength of 800 nm). Multiply charged carbon ions, up to C4+, were detected in the time-of-flight spectra. We have measured both energy and angular distributions with respect to the laser polarization direction for ions with different charge number. The kinetic energy of ions are distributed above 1 keV. The angular distribution measurement shows that the highly charged ions of C3+ and C4+ are mostly distributed in the directions parallel to the laser polarization, and the C+ ions are slightly distributed in the direction perpendicular to it. These observations clearly indicate that an anisotropic explosion takes place. The average energy of ions with the different charge number is found to be proportional to the square of the charge number, while the maximum energy is proportional to the charge number. Classical molecular dynamics simulations have been successfully carried out reproducing not only the energy spectra but also the angular distributions of ions. The C3+ ions are shown to be produced by the cascade hopping of electrons induced by the intense laser light. The simulations suggest that the most crucial process for the anisotropic Coulomb explosion of C60 is not the electron impact ionization, but the cascade hopping of electrons.

Cluster-assistant generation of multiply charged atomic ions in nanosecond laser ionization of seeded methyl iodide beam

“…The use of tunable dye lasers to produce resonantly enhanced multiphoton ionization (REMPI) provides a powerful method for investigating molecular energy levels [1][2][3][4][5][6]. On the other hand, the study of photoionization and fragmentation processes induced by ultra-intense lasers in atoms and molecules has been the subjects of recent researches [7][8][9][10][11][12][13][14][15][16][17]. The observation of highly charged atomic ions produced by intense laser beams has been widely reported [7][8][9][10][11][12][13][14].…”

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

“…The results indicate that field-induced nonadiabatic transition plays a decisive role in the reaction dynamics of molecules in intense laser fields [16,17]. Much attention has recently been paid to the competition between ionization and fragmentation of large molecules such as fullerenes [20,21]. It is known that C 60 interacting with a laser field of λ ≤800 nm decomposes into fragments, e.g., through the loss of C 2 -units [20].…”

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

“…Much attention has recently been paid to the competition between ionization and fragmentation of large molecules such as fullerenes [27,28]. It is known that C 60 interacting with a laser field of k 6 800 nm decomposes into fragments, e.g., through the loss of C 2 -units [27].…”