Contrôle quantique de grands systèmes moléculaires : application aux intersections coniques – CoConicS
CoConics
Contrôle quantique de grands systèmes moléculaires :<br />application aux intersections coniques
Quantum control of the ring-opening of spiropyran molecules
This project targets the control of quantum effects in large molecular systems possibly embedded in a<br />complex environment. We will focus on photochemical mechanisms in organic compounds where conical<br />intersections (CI) play a major role, more specifically on the ring-opening reaction for spiropyran molecules.<br />This formidable task, so far little studied, requires the development of innovative approaches combining<br />sophisticated models of quantum chemistry, the use of very recent programs for quantum dynamics, and<br />scenarios of control usually studied in applied mathematics, and in theoretical and experimental physics. A<br />major aspect comes from the fact that the molecular systems near a conical intersection feature a large<br />number of states: the population transfer does not expect to occur between single vibrational states but rather<br />between groups of a large number of (rovibrational) states leading to a wavepacket transfer. In this situation<br />we do not aim at controlling precisely the components of a wavepacket, but rather, for chemical applications,<br />its global structure such as its shape or its position. Another critical aspect concerns the identification<br />through active coordinates of an effective system leading to the desired process, and the conservation of its<br />coherence while it interacts with the rest of the sytem (the bath). The consortium has been carefully set up in<br />order to gather the necessary expertise in quantum chemistry, (theoretical and experimental) quantum<br />dynamics and control for the achievement of the project.
The 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 active
coordinates 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 a
genuine environment, and also the other inactive coordinates of the system and high-order perturbative field
effects).
(ii) The strategies of control that will be targeted should be robust both with respect to an imperfect
knowledge 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 theoreticians
and the experimentalists of the consortium during the project.
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.
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.
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.
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.
Coordination du projet
Benjamin LASORNE (Institut Charles Gerhardt Montpellier)
L'auteur de ce résumé est le coordinateur du projet, qui est responsable du contenu de ce résumé. L'ANR décline par conséquent toute responsabilité quant à son contenu.
Partenaire
ICB-B Laboratoire Interdiciplinaire Carnot de Bourgogne - Equipe B
LCP Laboratoire de Chimie Physique
ICB-A Laboratoire Interdiciplinaire Carnot de Bourgogne - Equipe A
ICGM Institut Charles Gerhardt Montpellier
Aide de l'ANR 452 846 euros
Début et durée du projet scientifique :
août 2013
- 48 Mois
