Theoretical study of femtosecond pump—probe signals of nonstoichiometric alkali halide clusters
We present the outline of the ab-initio molecular dynamics method for adiabatic excited states which is suitable to treat the involved excited electronic states simultaneously with the motion of the nuclei. The method allows the simulation of time-resolved pump-probe signals and the analysis of the signals in terms of the underlying nuclear dynamics. Moreover, the timescales of the structural relaxation in excited electronic states vs. intramolecular vibrational relaxation processes can be estimated and the influence of the initial temperature of the cluster can be determined.
The method is applied to the analysis of the timescales as well as of the dynamics of localized/delocalized electronic excitations in the Na2F molecule which represents a test example for nonstoichiometric alkali-halides with one excess electron. The aim is to develop a method for the investigation of time-dependent laser induced processes in clusters which is capable to extract the leading physical effects responsible for the controlled excitation dynamics and for the evolution of the non-equilibrium states.
PACS31.15.Ar Ab initio calculations 31.15.Qg Molecular dynamics and other numerical methods 31.50.+w Excited states 31.70.Hq Time-dependent phenomena: excitation and relaxation processes and reaction rates
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