Ionization and dissociation of linear triatomic molecules in strong laser fields

Abstract

Ionization of molecules in strong femtosecond laser fields is a key process for understanding a variety of strong-field molecular physical phenomena. In this study, we performed an experimental study on strong-field ionization and dissociation of three linear triatomic molecules, CO2, CS2, and OCS, using time-of-flight mass spectrometer. We measured the yield of different parent ions and various fragment ions as a function of laser intensity in the range of 2.0×1013W/cm2 to 8.0×1014W/cm2, in both 800-nm and 400-nm strong laser fields. The mechanism of strong-field single and double ionization, as well as fragmentation, was discussed based on the experimental results. In addition, the angular distributions of fragment ions were obtained. The results show the anisotropic distributions in the formation of highly charged atomic fragment ions, which may be attributed to the alignment of the molecules in strong laser fields before dissociation.