Experimental and theoretical study on nonsequential double ionization of carbon disulfide in strong near-IR laser fields

Abstract

Nonsequential double ionization (NSDI) of carbon disulfide ${\mathrm{CS}}_{2}$ in strong 800-nm laser fields is studied experimentally and theoretically. A knee structure is observed in the intensity-dependent double ionization (DI) yield in linearly polarized laser fields, which exhibits a strong dependence on the laser ellipticity. The electron momentum distributions and energy trajectories after DI in both linearly and circularly polarized laser fields are investigated by employing the two-dimensional classical ensemble method. The results clearly show the evidence of NSDI in the strong-field DI of ${\mathrm{CS}}_{2}$ molecules. It is demonstrated that, similar to that of atoms, NSDI of ${\mathrm{CS}}_{2}$ molecules is produced via laser-driven electron recollision with the ion core and presents electron-electron correlations in the process. Analysis indicates that both mechanisms in atomic strong-field NSDI, i.e., recollision impact ionization and recollision excitation with subsequent ionization, may also be contributed to NSDI of ${\mathrm{CS}}_{2}$ in strong laser fields. Further studies are no doubt necessary for a full understanding of the underlying physical mechanism of molecular strong-field NSDI, due to the multicenter character of the molecular structure and the complex molecular excited states that could be involved in the ionization.