Soutenance de thèse de Samrit Mainali EN VISIOCONFERENCE
Quantum control of the coupled motion of electrons and nuclei
soutenance de thèse de Samrit Mainali, ISMO
The study of quantum dynamics of large molecules is a bottleneck in the domain theoretical chemistry and physics. A proper simulation model shall be required to understand the processes like radiation-less transfer, internal conversion (IC) and photo dissociation, which are the signatures of presence of strong coupling between the excited states. For our study, we consider a molecule called Pyrazine, containing 24 normal modes and possessing a point of degeneracy among the excited electronic states, commonly known as conical intersection. Our theoretical model consists of using a short laser pulse within the limit of weak field regime and analyse (and ul- timately control) the partition of the wavepackets in different paths. This is the basis of mode selective chemistry, where we could interfere by guiding the lasers in the direction of reaction coordinate. We use a series of laser pulses so as to have a time interference between the lasers (route interference, as described elsewhere is not possible for symmetry reason). The calculations were performed by a software called MCTDH (Multi Configuration Time Dependent Hartree), the basis of which is the variational principle. The robustness and the efficiency of the model has been verified by systematic augmentation of dimensions from 2 to 4 to 24 normal modes. The quantum mechanical observable simulated is the electronic population.
Nous contacter avant lundi 21 février, 12h, pour obtenir le lien :
http://www.ismo.universite-paris-saclay.fr/spip.php?article2644
Quantum control of the coupled motion of electrons and nuclei
soutenance de thèse de Samrit Mainali, ISMO
The study of quantum dynamics of large molecules is a bottleneck in the domain theoretical chemistry and physics. A proper simulation model shall be required to understand the processes like radiation-less transfer, internal conversion (IC) and photo dissociation, which are the signatures of presence of strong coupling between the excited states. For our study, we consider a molecule called Pyrazine, containing 24 normal modes and possessing a point of degeneracy among the excited electronic states, commonly known as conical intersection. Our theoretical model consists of using a short laser pulse within the limit of weak field regime and analyse (and ul- timately control) the partition of the wavepackets in different paths. This is the basis of mode selective chemistry, where we could interfere by guiding the lasers in the direction of reaction coordinate. We use a series of laser pulses so as to have a time interference between the lasers (route interference, as described elsewhere is not possible for symmetry reason). The calculations were performed by a software called MCTDH (Multi Configuration Time Dependent Hartree), the basis of which is the variational principle. The robustness and the efficiency of the model has been verified by systematic augmentation of dimensions from 2 to 4 to 24 normal modes. The quantum mechanical observable simulated is the electronic population.
Nous contacter avant lundi 21 février, 12h, pour obtenir le lien :
http://www.ismo.universite-paris-saclay.fr/spip.php?article2644