Channel-resolved multiorbital double ionization of molecular Cl2 in an intense femtosecond laser field

We measure the sequential double ionization and the subsequent Coulomb explosion of molecular Cl2 in an intense femtosecond laser field by using the dc-sliced ion imaging technique. The results indicate that not only the highest occupied molecular orbital (HOMO) but also the next two lower-lying molecular orbitals are involved in three distinguished reaction pathways. Pathways (1,1)2 and (1,1)3 are both dissociated from Cl22+→Cl++Cl+, but with the two electrons removed from HOMO and HOMO-2 in reverse sequence, and populated on the ionic excited states Πg3 and Πg1, respectively. The kinetic energy release differences observed in these two channels are ascribed to the nuclear motion during the ionization process. For pathway (1,1)1 (also dissociated from Cl22+→Cl++Cl+) populated on the ionic excited states Πg1, the isotropic angular distribution of the fragment ions is attributed to the combination of the electron density distribution of HOMO-1, the vibrational electronic wave-packet evolution, and the field excitation. Our results propose a feasible method to manipulate the electronic dynamics which takes place in the attosecond time domain via accurately tuned laser parameters of a femtosecond laser field.