Toward understanding the breakup mechanism of triatomic molecular ions in an intense laser field*

Studies of laser-induced dissociation and ionization of triatomic molecular ions is a key step toward understanding the breakup mechanisms of complex systems in an intense laser field. This study is focused on two questions: (1) Does a triatomic molecular ion XY$_{2}^{+}$ bend during the interaction with a strong ultra-short laser field? (2) What is the preferred dissociation or ionization alignment relative to the laser polarization of such molecular ions? We implement a coincidence three dimensional momentum imaging technique, which allows us to measure all the neutral and charged fragments of any breakup channels of a triatomic molecular ion in coincidence. For example, we have studied a CO$_{2}^{+}$ ion beam, exposing it to intense 30 fs, 790 nm laser pulses with intensity up to 10$^{15}$ W/cm$^{2}$, in order to address the above questions.