Angular distributions of the fragments from Coulomb explosions of diatomicmolecules in intense laser fields

The angular distributions of the fragments from a Coulomb explosion of a di atomic heteronuclear molecule during multielectron dissociative ionization in a superintense field are considered in terms of classical mechanics. The patterns of angular distributions of the Coulomb explosion fragments are s hown to differ in different ranges of laser pulse parameters. In particular , there are two distinct modes of fragment separation: separation in a Coul omb field and separation in the field of an effective "fragment+field" pote ntial. The effective potential includes both the force of Coulomb repulsion between the fragments and the period-averaged force exerted on the system by the field; it can be determined by using the Kramers-Henneberger method. The limits of applicability of the Kramers-Henneberger method to the probl em in question are discussed. These limits specify the range of field param eters in which the fragments fly apart in a direction perpendicular to the field for the initially arbitrary orientation of the molecular axis relativ e to the field. (C) 2001 MAIK "Nauka/Interperiodica".