CHARISMA · CHARge transport in Intermediate-Sized Molecules on Attosecond time scales
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2018-09-01 → 2020-08-31
- EU contribution
- €168,277
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
Lines connect the coordinator with its partners.
Results in brief
CHARge transport in Intermediate-Sized Molecules on Attosecond time scales
Attosecond science has been a very active field of research for almost 20 years now and ultrafast electron dynamics in atoms and small benchmark molecules have drawn a lot of attention. Typically, pump-probe experiments are performed, in which an attosecond pulse in the extreme ultraviolet (XUV) generated by high harmonic generation induces ultrafast photoionization dynamics, which are probed in a delayed femtosecond infrared (IR) field coherent with the pump pulse, since XUV+XUV pump/probe schemes are not yet feasible for a wide range of applications. The choice of observables, in which the ultrafast dynamics are encoded, is however not straightforward especially for complex targets. In addition, the full theoretical description of electron dynamics on the attosecond time scale and the coupling to nuclear motion requires high computational costs and are thus not yet applicable for large target systems. However, there is a huge interest in the physics and chemistry community to push the boundaries in attosecond science towards more complex molecules to understand the underlying processes and ultimately gain control over the electron dynamics, which control the outcome of a photoionization reaction. This might make it possible to steer the latter with an unprecedented precision. Upon photoionization with an attosecond pulse in the XUV, a molecule is ionized into a coherent superposition of ionic states, which can lead to ultrafast oscillations of the charge density (charge migration) along the molecular backbone before nuclear dynamics set in after few femtoseconds. These coupled electron-nuclear dynamics can then lead to charge localization and finally induce a fragmentation. Only few experimental studies report on the observation of charge migration in molecules. CHARISMA aimed at gaining deeper insights how to study these ultrafast dynamics experimentally at the well-equipped attosecond laboratory at Politecnico di Milano, Italy. The focus was on intermediate-sized molecules of 10-20 atoms with structures found similarly in more complex molecules of biological-relevance, such as amino acids and proteins, and DNA bases.
Data: CORDIS, © European Union
Project objective
The CHARISMA project will investigate ultrafast charge transport induced by photoionization in intermediate-sized molecules. Charge migration is mediated purely by electronic dynamics on time scales down to hundreds of attoseconds. The subsequent interplay with nuclear dynamics on the femtosecond time scale can lead to charge transfer and localization. These ultrafast mechanisms play important roles in the interaction of ionizing radiation with biologically-relevant molecules, in molecular electronics, and also in astrochemistry. To gain fundamental insights into ultrafast charge transport it is necessary to study it in smaller molecules that are more tractable for experimental and theoretical methods. Such studies hold the promise to direct charge migration for controlling chemical reactivity, which would impact many chemical disciplines. Numerous theoretical studies have already addressed charge migration, but only recently advances in high-harmonic generation (HHG) sources, providing intense, ultrashort XUV pulses have made ‘real time’ experiments possible. It is therefore timely to study ultrafast charge transport in intermediate-sized molecules. These results will stimulate ongoing technical developments to extend the techniques to complex molecules of practical relevance in the near future. In pursuing this goal, CHARISMA relies also on coincidence experiments using synchrotron radiation to facilitate the challenging choices of meaningful experimental observables for the time-resolved studies. The researcher’s large experience in molecular photoionization using a variety of advanced light sources will be extended in this project, for which the state-of-the-art ultrafast lasers at Politecnico di Milano provide the perfect environment. CHARISMA integrates perfectly into the vibrant community of attosecond science in Europe and will demonstrate the synergy of synchrotron and HHG radiation in the pursuit of molecular control through ultrafast charge migration.
Original text from CORDIS.
Participants
- POLITECNICO DI MILANO · MilanoCoordinatorItaly
Links
Data: CORDIS, © European Union