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Steering attosecond electron dynamics in biomolecules with UV-XUV LIGHT pulses

Periodic Reporting for period 3 - STARLIGHT (Steering attosecond electron dynamics in biomolecules with UV-XUV LIGHT pulses)

Reporting period: 2018-03-01 to 2019-08-31

The main goal of the project is to study the electron dynamics resulting from the interaction of biomolecules with light. Elementary mechanisms activated by the light-molecule interaction are at the basis of more complex chemical and biological processes such as photosyntesis, energy transfer, vision, DNA damage and repair. These elementary mechanisms often occur on an ultrafast time scale. By using the shortest light pulses currently available (attosecond pulses: 1 as = 10^-18 s) we can capture the activated electronic motion in the biomolecules in real-time. We would like to understand the role of this ultrafast dynamics in the photophysics of the biomolecule. Particular attention is devoted to DNA building blocks with the aim of tracking the electronic charge redistribution activated by ultraviolet (UV) light (penetrating our atmosphere) and potentially leading to damage.

By fulfilling the objectives of the project, it will be possible to follow and control the ultrafast electronic charge flow in our own biomolecules and obtain the full elucidation of the role of the electron dynamics, following UV-excitation of biomolecules, in the possibility to prevent/favor subsequent structural changes leading to damage.

New horizons for photo-chemistry and photo- biology, with tremendous prospects in phototherapy, will be disclosed by the thorough elucidation of the role of the electron dynamics in the more complex processes occurring at later times. Moreover, we aim at manipulating the electronic motion in molecular junctions. Important implications can be foreseen in the fields of quantum electronics and quantum computing, providing new insights for the design of ultrafast switching devices and laser-driven single-gate qubit.
The action officially started on April 1st, 2015. Since September 2016, the Principal Investigator (PI) has been employed as leading scientist at DESY and a consortium of the former (CNR-IFN) and present (DESY) Host Institutions has been created (see Amendment to the Grant Agreement No 637756). The activities up to the mid-term of the action period have been entirely carried out in the attosecond laboratory of CNR-IFN directed by the PI.

The start-up phase of the project consisted in the following steps:
• Project management and coordination;
• People recruitment: two Post Docs, one PhD student, one visiting PhD student and one master student;
• Acquisition of equipment;
• Acquisition, design and realization of specific components for the construction of the high-energy attosecond beamline, the UV source and the biomolecular source;
• Creation of STARLIGHT logo and facebook webpage (https://www.facebook.com/erc.starlight/).

After the start-up phase the work has been carried according to the project objectives:

Obj. 1 Development of a UV pump – XUV attosecond probe beam-line with high photon-flux.
Obj. 2 Development of a few-cycle UV source for UV pump - UV probe experiments.
Obj. 3 Study of the electron dynamics in biomolecular subunits.
Obj. 4 Control of the electron dynamics in cyclic biomolecules.
Obj. 5 Study of the electron dynamics in DNA double helix.

Obj. 1-2 have been completed and Obj. 3-4 will be completed by the end of the action (2020). We have developed i) beyond state-of-the-art attosecond technology, ii) an ultrashort (<2fs) UV light source, iii) a source of biomolecules in gas-phase and iv) a double spectrometer for the simultaneous detection of electrons and ions. All these technologies will enable time resolved studies of the electron dynamics in biomolecules to be performed in the second part of the action.

The work conducted until the mid-term of the project resulted in 17 publications on peer-reviewed journals (including Nature Physics, Nature Photonics, Nature Communications, Chemical Review), 21 contributions to international conferences (12 invited lectures), 7 contributions to international workshops, 3 contributions to Schools and 10 invited seminars.
We have developed
i) beyond state-of-the-art attosecond technology;
ii) an ultrashort (<2fs) UV light source;
iii) a source of biomolecules in gas-phase;
iv) a double spectrometer for the simultaneous detection of electrons and ions.

The developed technologies have allowed preliminary time resolved measurements in biomolecular subunits including DNA nucleobasis and nucleosides. We expect to extend the same time-resolved investigation to the UV-excited subunits in the second part of the action.
Picture of laser light in the attosecond beamline
Picture of STARLIGHT team working on the attosecond beamline
STARLIGHT logo
Picture of laser light in the attosecond beamline
Picture of laser light in the attosecond beamline
Picture of laser light in the attosecond beamline
Picture of STARLIGHT team working on the attosecond beamline
Picture of STARLIGHT team working on the attosecond beamline