The advent of ultrashort pulses produced by free-electron lasers and high harmonic generation has opened up the way to a new chemistry at the femto and attosecond time scales. Processes such as laser induced ionisation and dissociation can now be monitored in real time and can be used to control chemical reactions. However, the dynamics of charge transfer (CT) processes taking place in a collision have never been investigated. ATTONEW aims at analyzing the mechanism of CT during an ion-biomolecule collision in real time for the first time. Novel time-dependent (TD) wavepacket propagation methods will be developed to follow the attosecond nuclear and electron motion involved in the collision. Moreover, we will also explore the possibility of controlling the reaction by preparing electronic wavepackets in the Uracil molecule. The methodology will be applied to the interactions between carbon ions, C2+ and C4+, with the RNA base Uracil. CT in ion-biomolecule systems is interesting since it is responsible for cancer disease and controlled cell killing used in radiotherapy. Such complex systems demand detailed knowledge of the potentials energies and non-adiabatic couplings between the states involved in the process; these will be obtained with high level ab initio multiconfigurational methods. Due to the high energies involved in the collision (keV), the proposed dynamical calculations are memory extensive requiring algorithm parallelization. We propose two different TD scenarios in which wavepackets will be simulated first, in one dimension (assuming a single attack direction), and second, in two dimensions (considering a planar and a perpendicular attack). Combining these two attacks, we will obtain anisotropic features of the global three-dimensional collision process, directly comparable with the experiment. Most importantly, our wavepacket simulations will discover the attosecond time-resolved mechanism of a CT process in an collision of the Cq+ ion with Uracil.
Field of science
- /natural sciences/physical sciences/optics/laser physics
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