Electronic and vibronic excitations as well as fragmentation mechanisms in high energy ion ( H+, C+, Ar+) fullerene collisions are investigated within a fully microscopic approach, called nonadiabatic quantum molecular dynamics. The total kinetic energy loss of the projectile depends dramatically on ion mass, but, surprisingly, does not depend on the impact velocity for all ions in a certain range. This is in striking contrast to the predictions of the "stopping power" concept of solids, but explains apparently contradicting experimental observations. Signatures for nonstatistical fragmentation mechanisms are predicted.

A generalized formalism of the so-called non-adiabatic quantum molecular dynamics is presented, which applies for atomic many-body systems in external laser fields. The theory treats the nuclear dynamics and electronic transitions simultaneously in a mixed classical-quantum approach.Exact, self-consistent equations of motion are derived from the action principle by combining time-dependent density functional theory in basis expansion with classical molecular dynamics.Structure and properties of the resulting equations of motion as well as the energy and momentum balance equations are discussed in detail. Future applications of the formalism are briefly outlined.

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The dynamics of the ethylene molecule in femtosecond laser pulses is studied as a function of the laser parameters using an ab initio time-dependent approach, called nonadiabatic quantum molecular dynamics. We predict that, by choosing different femtosecond pulses with well-defined excitation frequencies, one can selectively induce either the isomerization process or different fragmentation phenomena.

We propose a novel method to describe realistically ionization processes with absorbing boundary conditions in basis expansion within the formalism of the so-called Non-Adiabatic Quantum Molecular Dynamics. This theory couples self-consistently a classical description of the nuclei with a quantum mechanical treatment of the electrons in atomic many-body systems. In this paper we extend the formalism by introducing absorbing boundary conditions via an imaginary potential.It is shown how this potential can be constructed in time-dependent density functional theory in basis expansion. The approach is first tested on the hydrogen atom and the pre-aligned hydrogen molecular ion H + 2 in intense laser fields where reference calculations are available. It is then applied to study the ionization of non-aligned H + 2 and H 2 . Striking differences in the orientation dependence between both molecules are found. Surprisingly, enhanced ionization is predicted for perpendicularly aligned molecules.