A theoretical analysis of the time-resolved femtosecond CARS spectrum of I2

We analyze the results of recent femtosecond CARS-experiments on the iodine molecule within time-dependent quantum calculations. Dependent on the delay-time between three ultrashort pulses, the third-order polarization shows oscillations which are characteristic for the wave packet motion in the electronic ground or B excited state. For the overall dependence of the CARS-signal on the pulse delay the treatment of the vibrational degree of freedom is sufficient. The specific decay and long time behaviour of the recorded signals however, can only be understood if the rotational degree of freedom is taken into account.