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Attosecond dynamics of ion-biomolecule collisions by nuclear and electron wavepackets

Final Report Summary - ATTONEW (Attosecond dynamics of ion-biomolecule collisions by nuclear and electron wavepackets)

The aim of the ATTONEW project was to examine, from a theoretical point of view, the mechanism of charge transfer (CT) process in a molecular collision, taking place in the femto- (1 fs=10-15 s) or atto-second (1 as=10-18 s) time scale. The investigation of such a mechanism in real time is a pioneer application in the newly born field of Attochemistry.
Domains like molecular electronics, bioinformatics and cancer research should benefit in the long-term from a detailed understanding of the CT process.
As an example, the collision of carbon ions Cq+(q=2,4) with the RNA base Uracil was considered. To study this process a novel time-dependent wavepacket method was developed. State-of-the-art quantum chemistry methods were merged with wavepacket propagation approaches, allowing for the real time investigation of the mechanism of CT in the proposed systems (Fig. 1). In the low-energy range of [1-10] eV, the collisional process can be described as the evolution of a quasi-molecule formed from the ion-molecule system in which the reaction coordinate corresponds to the distance R between the centre of mass of Uracil and the colliding carbon ion. In a first step, the study of the CT mechanism necessitates the calculation of the potential energies of the states involved in the process, as well as the couplings between these states. These are obtained using high level ab initio quantum chemical methods. In the second step, the time-resolved aspects of the ultrafast collision are to be studied using time-dependent wavepacket formalisms. One- (1D) and twodimensions (2D) scenarios can be set up, which allow, among others, the calculation of the explicit time evolution of the electronic charge. The electronic density of the system allows to follow the charge exchange mechanism in real time.