Collision induced dissociation of the heteronuclear alkali ion NaK

An experimental study of the dissociation of the heteronuclear Na${\rm K^+}$ ion by collisions with He and H2 targets at a collision energy of 2.4 keV is presented. The use of a technique based on the measurement of the velocity vectors of the fragments allows investigating in detail the two basic dissociation mechanisms: impulsive and electronic. In the present asymmetric case, one is able to assess the relative role of close encounters with each of the Na+ and ${\rm K^+}$ atomic cores of the molecule. Electronic transitions at a surface crossing are proposed to explain processes which happens in close collisions between the ${\rm K^+}$ core and the He target