• "DNA oligomers"
• "excitonic model"
• "fluorescence decay"
• "local diabatization"
• "mixed quantum-classical dynamics"
• "nonadiabatic dynamics"
• "surface hopping"

In this thesis, HP6 double strand (a DNA oligomer made of adenine and thymine) excited state behaviour is studied, employing an implementation of Frenkel exciton model in a semiempirical (AM1) framework. After an initial full-MM (Tinker) and subsequent QM/MM (NewtonX) Thermalizations, spectra (both adiabatic and diabatic) are produced. In the following, excited state nonadiabatic dynamics is performed (NewtonX), allowing a collective of trajectories to decay to ground state. The results are analyzed and fluorescence decay pathways are proposed, based on excitation localization on chromophores and transfer of excitation among them.