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Tesi etd-01152019-171016


Tipo di tesi
Tesi di dottorato di ricerca
Autore
MENGER, MAXIMILIAN FRIEDERICH SEBASTIAN JOHANNES
URN
etd-01152019-171016
Titolo
Development of Multiscale Models for the Static and Dynamic Description of Photoinduced Processes in Embedded Systems
Settore scientifico disciplinare
CHIM/02
Corso di studi
SCIENZE CHIMICHE E DEI MATERIALI
Relatori
tutor Prof.ssa Mennucci, Benedetta
relatore Prof.ssa Gonzalez, Leticia
commissario Prof. Pescitelli, Gennaro
commissario Prof.ssa Chiellini, Federica
commissario Prof. Castelvetro, Valter
commissario Dott. Tavernelli, Ivano
commissario Prof.ssa Burghardt, Irene
commissario Prof. Persico, Maurizio
commissario Dott. Rizzo, Antonio
Parole chiave
  • Exciton Model
  • Molecular Dynamics
  • QM/MM
  • Quantum Mechanics
  • Surface Hopping
Data inizio appello
18/01/2019
Consultabilità
Completa
Riassunto
The detailed knowledge of the processes following photoexcitation is
extremely important, but the understanding of the underlying mechanisms, as
well as the proper description of the corresponding non-adiabatic dynamics
are still real challenges for theoretical chemistry. This is true especially for
biologically relevant systems, where not only the chromophores, but also
the complex environment need to be included in the simulation in order to
obtain a correct picture. The environment, in fact, can play an important
role in the mechanisms of the photoinduced processes by tuning both the
electronic and structural properties of the chromophore(s). In this thesis, we
present novel computational multiscale models, based on a hybrid quantum
mechanical/molecular mechanical (QM/MM) description of the system able
to study such processes.
First, the theoretical formulation and implementation of excited states
gradients of a polarizable QM/MM method using an induced dipole scheme
are introduced within the framework of time-dependent density functional
theory. Secondly, the development and the implementation of a novel exciton
approach are presented and discussed, where the environment is included
via an electrostatic or mechanical embedding scheme. Consistent hybrid
QM/MM energies, gradients and non-adiabatic couplings were developed,
allowing ab initio non-adiabatic dynamics simulations in multichromophoric
systems, using the surface hopping approach.
The methods are finally applied to the study of (i) the effects of a DNA
pocket on the excitation process and the corresponding excited state properties
of an organic dye, and (ii) the excitation energy transfer process in an
orthogonal molecular dyad.
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