Multielectron dissociative ionization of diatomic molecules in an intense femtosecond laser field

Abstract

The multielectron dissociative ionization of diatomic molecules is investigated using an intense laser field at a wavelength of 615 nm, in the ${10}^{15}$ W/${\mathrm{cm}}^2$ intensity range, with a 100-fs pulse duration. Comparison with previous experiments performed with 2-ps and 600-fs pulse durations shows that the atomic-ion kinetic-energy releases depend neither on the laser-pulse duration nor on the peak laser intensity. The simple model of Coulomb repulsion between atomic ions is therefore insufficient to account for the dynamics of the multiple-ionization mechanism. Comparison between ${\mathrm{N}}_2$, CO, and ${\mathrm{O}}_2$ experiments indicates that the channel ${\mathit{AB}}^{2+}$→${\mathit{A}}^{+}$+${\mathit{B}}^{+}$ remains molecule specific. Conversely, the channels involving molecular ions carrying higher charges (${\mathit{AB}}^{(\mathit{p}+\mathit{q})+}$→${\mathit{A}}^{\mathit{p}+}$+${\mathit{B}}^{\mathit{q}+}$) exhibit similar dissociation energies for ${\mathrm{N}}_2$, CO, and ${\mathrm{O}}_2$.