Dissociative ionization of benzene in intense ultra-fast laser pulses

Based on the possibility of multiphoton ionization of the inner valence ele ctrons in polyatomic molecules, a model was proposed to predict the abundan ce of different fragments resulting from dissociative ionization of the pol yatomic molecules interacting with short laser pulses. According to this mo del the fragmentation of these molecules occurs through multiphoton ionizat ion of the inner valence electrons, which results in a molecular ion in an excited state. Through radiationless transition the population is transferr ed to the highly excited levels of the ground electronic state. The molecul ar ion created in this manner is not stable and dissociates rapidly. To tes t the applicability of the model, the fragmentation of a benzene molecule i nteracting with linearly and circularly polarized Ti:sapphire laser pulses was studied. The model was tested by comparing the measured laser-intensity -dependent abundance of C4H4+ fragment ions with the calculated ones and ex cellent agreement was obtained with the experimental results.