Table of Contents
Laser Chemistry
Volume 5, Issue 3, Pages 119-132

Computer Simulations of Viscosity Dependent Molecular Relaxation Processes

Physics Department, Friedrich-Schiller-Universität Jena, Jena GDR 6900, Germany

Received 18 June 1983; Accepted 10 April 1984

Copyright © 1985 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The dependence of excited-state lifetime, fluorescence quantum yield and isomerization rate of organic dye molecules on solvent viscosity has been a subject of numerous experimental and theoretical investigations. To explain the viscosity dependence of excited-state lifetime in this paper the temporal behavior of the excited state population is calculated for several models of the molecular relaxation process by a computer simulation incorporating both the stochastical motion of large molecular parts in the excited state and relaxation transitions. The described method is applicable to calculating the probability of changing the electronic state as a function of time and internal rotation coordinate.