Quantum control spectroscopy of molecular photomechanical transducers


The project aims at implementing Quantum Control Spectroscopy (QCS) as a powerful tool to unravel and control the mechanisms which govern the dynamics and yield of ultrafast photoreactions involved in photomechanical or photoelectrical energy transduction at the molecular scale in condensed phase. To this end, we will develop a new research activity combining experimental and theoretical approaches by implementing Vibrational Coherence Spectroscopy (VCS) and Quantum Control (QC), together with state-of-the-art quantum chemistry and molecular trajectory computations.

Within this frame, the present proposal requests financial support for new experimental developments and manpower. A dedicated VCS set-up will be built based on a new laser system producing sub 10-fs, 800-nm and 400-nm laser pulses. VCS will be used to unravel the vibrational dynamics driving ultrafast photoreactions.

Simultaneously, QCS will be implemented by spectro-temporal shaping of the 400-nm excitation pulse to tailor vibrational coherence in specific vibrational modes so as to alter the reactive motion. Following a rational, theory-guided strategy, we will investigate the effect of various simple Quantum Control strategies on the vibrational dynamics and on the quantum yield of ultrafast photoreactions. The approach will first be applied to molecular photo-switches, which exhibit outstanding vibrationally coherent photo-isomerization and are computationally tractable with state-of-the-art theoretical approaches. These photo-switches will thus serve as a model system to understand the mechanisms governing the photoreaction dynamics and yield and to investigate the possibility of controlling coherently the photo-reactive motions.

The developments and resulting findings will allow us to apply VCS and possibly quantum control on other ultrafast photoreactions, including photo-isomerization in other systems or ultrafast charge transfer in organic compounds or in proteins. The ambition of the project is to open new routes towards the rational design and/or optical control of molecular systems for photomechanical or photoelectrical conversion.