ERC ATTOP – ATTOsecond Photochemistry: controlling chemical reactions with electrons

ATTOP is a theoretical chemistry project led by Morgane Vacher aiming to explore the synergy between the two fields of attosecond science and photochemistry. ATTOP has been funded by a 1.5 M€ ERC Starting Grant (n° 101040356, 2022-2027).

5-year project

2022 - 2027

1 496 142 €

ERC funds


person-months effort over the 5 years


Internal team members

The goal of the ATTOP project is to develop a general know-how to design electronic wavepackets and attosecond experiments hence transforming the outcome of photochemical reactions.

Photochemical reactions often lack control and selectivity. To overcome this fundamental limitation, ATTOP proposes to bring very recent technological progress in ultrashort light pulses and will simulate accurately chemical reactions induced by electronic wavepackets via attosecond pulses.

In more details

Chemical processes initiated by light are extremely widespread and their applications cover vital research fields such as medicine, computing and energy conversion.

However, photochemical reactions are limited by the nature and finite number of excited electronic states of molecules and therefore often lack control and selectivity.

To overcome this fundamental limitation, ATTOP proposes to bring recent technological advances in attosecond science to photochemistry and to explore the emerging field of "atto-photochemistry". Indeed, light pulses of attosecond duration have a large spectral width and excite several excited electronic states simultaneously and coherently. This superposition, called "electronic wavepacket", has a new electronic distribution and should therefore lead to a new chemical reactivity. The following question remains unanswered for the moment: What is the reactivity of a molecule in these new types of experimentally accessible electronic states?

The emerging field of atto-photochemistry requires significant theoretical support from the outset. With a unique combination of expertise in both attoscience and theoretical photochemistry, the ATTOP team aims to accurately describe chemical reactions induced by electron wavepackets via attosecond pulses. The ultimate goal is to develop a general know-how to design electron wavepackets and attosecond experiments transforming the result of photochemical reactions for various applications.

Project team

Morgane VACHER

CNRS researcher

Project leader



Cluster supercomputing

Stéphanie TESSIER

Project manager

Finances, human resources, management and reporting

Thierry TRAN