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

The multielectron dissociative ionization of diatomic molecules is investigated using an intense laser field at a wavelength of 615 nm, in the 10¹⁵ W/cm² 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 N₂, CO, and O₂ experiments indicates that the channel AB²⁺→A⁺+B⁺ remains molecule specific. Conversely, the channels involving molecular ions carrying higher charges (AB^(p+q)+→A^p++B^q+) exhibit similar dissociation energies for N₂, CO, and O₂.