Projet ANR-13-BS08-0013 – CoConicS : Contrôle quantique de grands systèmes moléculaires : application aux intersections coniques
Programme : Blanc - SIMI 8 - Chimie du solide, colloïdes, physicochimie (Blanc SIMI 8)
Année de financement : 2013
Coordinateur du projet : Monsieur fabien GATTI (Institut Charles Gerhardt Montpellier)
Partenaires : Institut de Chimie Moléculaire et des Matériaux - Institut Charles Gerhardt Montpellier; Laboratoire de Chimie Physique; Laboratoire Interdisciplinaire Carnot de Bourgogne; Laboratoire Interdisciplinaire Carnot de Bourgogne
Montant : 452846.0 euros
Date de début : 2013
Durée : 48 mois
Résumé : CoConicsContrôle quantique de grands systèmes moléculaires :application aux intersections coniques
Quantum control of the ring-opening of spiropyran moleculesThis project targets the control of quantum effects in large molecular systems possibly embedded in acomplex environment. We will focus on photochemical mechanisms in organic compounds where conicalintersections (CI) play a major role, more specifically on the ring-opening reaction for spiropyran molecules.This formidable task, so far little studied, requires the development of innovative approaches combiningsophisticated models of quantum chemistry, the use of very recent programs for quantum dynamics, andscenarios of control usually studied in applied mathematics, and in theoretical and experimental physics. Amajor aspect comes from the fact that the molecular systems near a conical intersection feature a largenumber of states: the population transfer does not expect to occur between single vibrational states but ratherbetween groups of a large number of (rovibrational) states leading to a wavepacket transfer. In this situationwe do not aim at controlling precisely the components of a wavepacket, but rather, for chemical applications,its global structure such as its shape or its position. Another critical aspect concerns the identificationthrough active coordinates of an effective system leading to the desired process, and the conservation of itscoherence while it interacts with the rest of the sytem (the bath). The consortium has been carefully set up inorder to gather the necessary expertise in quantum chemistry, (theoretical and experimental) quantumdynamics and control for the achievement of the project.
Theoretical simulations with MCTDH and experimental work with laser pulsesThe achievement of the project is based on the following aspects.(i) From the complete system dressed by the fields, we will derive an effective system described by activecoordinates and dominant field effects (such as resonances) which will mainly lead to the desired process.The rest of the system will be considered as a perturbative environment or bath (which includes thus agenuine environment, and also the other inactive coordinates of the system and high-order perturbative fieldeffects).(ii) The strategies of control that will be targeted should be robust both with respect to an imperfectknowledge of the complete system and to possible fluctuations of the driving fields.(iii) The scenarios of control will be elaborated through continuous cooperation between the theoreticiansand the experimentalists of the consortium during the project.
Résumé de la soumission : Le présent projet a pour objectif de construire un consortium rassemblant toutes les expertises nécessaires en chimique quantique, dynamique quantique et contrôle quantique dans le but d'étudier à la fois d'un point de vue théorique et expérimental le contrôle laser à un niveau quantique de molécules de relativement grande taille. Nous nous intéresserons à des réactions chimiques impliquant des intersections coniques (processus de désexcitation non-radiative non-adiabatique c'est-à-dire hors Born-Oppenheimer) tels que l'ouverture de cycle dans les molécules de type spiropyrane. Un modèle pour les surfaces diabatiques à 48 dimensions pour le benzopyran sera développé et nous utliserons la récente méthode Multi-layer Multi-Configuration Time-Dependent approach (ML-MCTDH) pour simuler la dynamique quantique du système en présence de champs lasers (dynamique à 48 dimensions). Des stratégies systématiques de contrôle de la photoréactivité du système vont être développés d'un point de vue théorique (à l'aide d'une approche en termes de molécules "habillées" par les champs lasers) et implémentés à un niveau expérimental. Nous pensons combiner et améliorer des approches de type pompe-sonde, effet Stark, optimisation par feedback, ecxitation vibrationnelle préliminaire ou d'autres en collaboration directe entre les expérimentateurs et les théoriciens du consortium.
Résultats : The consortium has already given rise to five important publications:
L. Joubert Doriol, B. Lasorne, C. Raynaud, D. Lauvergnat, H.-D. Meyer, and F. Gatti,
«A generalized vibronic-coupling Hamiltonian model for benzopyran.« 
J. Chem. Phys., 140 (2014) 044301.
M. Saab, B. Lasorne,  S. Guérin, and F. Gatti,
«A quantum dynamics study of the benzopyran ring opening guided by laser pulses.« 
 Chem. Phys., 442  (2014) 93.
M. Sala, M. Saab, B. Lasorne,  F. Gatti, and S. Guérin,
«Laser control of the radiationless decay in pyrazine using the dynamic Stark effect.«, J. Chem. Phys.,  140, (2014) 194309.
M. Saab, M. Sala, B. Lasorne,  F. Gatti, and S. Guérin,
«Full-dimensional control of the radiationless decay in pyrazine using the dynamic Stark effect.«, J. Chem. Phys., 141,  (2014) 134114.
M. Sala, B. Lasorne,  F. Gatti, and S. Guérin,
«The role of the low-lying dark npi* states on the physics of pyrazine: a quantum dynamics study.«, P.C.C.P.,  16, (2014) 15957.
Perspectives : The project is strongly based on a continuous interaction between the experimental group and the chemistry
and physics theoreticians. A systematic feedback between the two will be necessary to choose the strategies
of control, optimise the parameters and to interpret the results. For instance: how can we choose the intensity
and the frequency of the pulse to guide the process with the Stark effect, with a preliminary vibrational excitation? How can we interpret theoretically the experimental feedback optimisation procedure in order to
highlight general trends that could be applied to other systems in the future? How is possible to block the
reaction (photostability) or to enhance it (photoreactivity) with a pump-dump procedure? The project gathers
all the expertises in theory to answer these questions and to improve the theoretical models if necessary:
quantum chemistry, quantum dynamics and theoretical control of reactions (adiabatic Floquet theory or
optimal control). One goal will be to trigger an interaction between theoretician chemists and
experimentalists on quantum control that could be pursued in the future in order to apply quantum control on
even larger chemical systems at the interface with the biology.
Publications et brevets : The consortium has already given rise to five important publications:
L. Joubert Doriol, B. Lasorne, C. Raynaud, D. Lauvergnat, H.-D. Meyer, and F. Gatti,
«A generalized vibronic-coupling Hamiltonian model for benzopyran.« 
J. Chem. Phys., 140 (2014) 044301.
M. Saab, B. Lasorne,  S. Guérin, and F. Gatti,
«A quantum dynamics study of the benzopyran ring opening guided by laser pulses.« 
 Chem. Phys., 442  (2014) 93.
M. Sala, M. Saab, B. Lasorne,  F. Gatti, and S. Guérin,
«Laser control of the radiationless decay in pyrazine using the dynamic Stark effect.«, J. Chem. Phys.,  140, (2014) 194309.
M. Saab, M. Sala, B. Lasorne,  F. Gatti, and S. Guérin,
«Full-dimensional control of the radiationless decay in pyrazine using the dynamic Stark effect.«, J. Chem. Phys., 141,  (2014) 134114.
M. Sala, B. Lasorne,  F. Gatti, and S. Guérin,
«The role of the low-lying dark npi* states on the physics of pyrazine: a quantum dynamics study.«, P.C.C.P.,  16, (2014) 15957.