Theoretical study of femtosecond pump-probe signals of nonstoichiometric alkali halide clusters

We present the outline of the abinitio molecular dynamics method for adiaba tic excited states which is suitable to treat the involved excited electron ic states simultaneously with the motion of the nuclei. The method allows t he simulation of time-resolved pump-probe signals and the analysis of the s ignals in terms of the underlying nuclear dynamics. Moreover, the timescale s of the structural relaxation in excited electronic states vs. intramolecu lar 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 d ynamics of localized/delocalized electronic excitations in the Na2F molecul e 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 e xtract the leading physical effects responsible for the controlled excitati on dynamics and for the evolution of the non-equilibrium states.