Photochemistry pp 119-140 | Cite as

Wavepacket Dynamics and Geometrical Relaxation

Chapter
Part of the Theoretical Chemistry and Computational Modelling book series (TCCM)

Abstract

In this chapter we shall present the dynamics that takes place after electronic excitation, under the influence of the new potential energy surface (PES). Nonadiabatic transitions to other electronic states will be assumed to be slow enough as to be neglected, so we shall qualify this topic as “adiabatic dynamics.” We shall examine the basic features of quantum wavepacket dynamics, and we shall find that some details of the excitation process affect the nature and the time evolution of the excited state even after the end of the radiation pulse. We shall see how, in certain conditions, quantum dynamics can be described with classical concepts, that are easier to grasp and provide the common language of qualitative arguments about reaction dynamics. The effects of the chemical environment on the dynamics of excited molecules will also be considered, trying to distinguish between interactions that change the PES and energy flow processes, i.e., the “static” and the “dynamic” effects, respectively.

Keywords

Franck-Condon excitation Adiabatic dynamics Ehrenfest theorem Intramolecular vibrational energy redistribution Thermalization Environmental effects 

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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Chemistry and Industrial ChemistryUniversity of PisaPisaItaly

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