2-STEP COULOMB EXPLOSIONS OF DIATOMS IN INTENSE LASER FIELDS

A two-step model of Coulomb explosions of diatoms in intense laser fie lds is presented. In this model the molecule loses several electrons w hen the atoms are at the equilibrium internuclear distance and then fa st Coulomb explosions occur until the products reach a critical distan ce R(c) congruent to 9 Bohr, at which several additional electrons are lost due to a recently discovered maxima of ionization rates occurrin g at R = R(c). Then the subsequent Coulomb explosion for the higher-ch arged ions takes place. The total combined Coulomb explosion energy ag rees well with experimental results, showing striking regularities. Th e origin and intensity dependence of unexpectedly high ionization rate s of dissociating nuclei at preferential, large internuclear distances R = R(c) is also discussed and an analytic expression for R(c) is der ived.