Strong-field dissociation of CS$^{2+}$ via a pump/dump-like mechanism*

Laser-induced dissociation of the quasi-bound electronic ground state of CS$^{2+}$ is investigated in intense laser pulses ($<$55 fs, $<$10$^{16}$ W/cm$^2$). Photodissociation is observed to be the dominant dissociation pathway; however, a more curious feature in the kinetic energy release spectrum suggests no significant energy gain from the initial states. We propose a pump/dump-like mechanism to explain this observed feature. Contrary to the conventional pump/dump control scheme, this process occurs within a single laser pulse, where the time delay is caused by the molecular structure. The process begins when the vibrational wavepacket in the electronic ground state of CS$^{2+}$ is pumped into the electronic first excited state's continuum by a single photon. After a period of stretching at an energy above the potential barrier, the emission of a second photon is stimulated by the same laser pulse, most likely at the Condon point.