MODE EXCITATION DYNAMICS IN THE FRAGMENTATION OF AR-3(- AN HELICITY DECOUPLING STUDY() )

A full quantum study of the fragmentation dynamics for argon trimer io ns is carried out using a previously computed potential energy surface (PES). The initial and final internal states which are being consider ed are the bending-stretching states of the trimer and the rotovibrati onal states of the residual dimer ion. The treatment employs the helic ity decoupling approximation over a broad range of total angular momen tum values (J) and analyses the final distribution of rotational-vibra tional states as a function of the metastable states of the J values a nd of the ''tumbling'' (helicity) quantum number \Omega\. It is found that at least two different effects, one mainly dynamically related to the centrifugal barrier and another to the orientational nature of th e coupling potential field, can be discerned to explain the fragmentat ion results. (C) 1997 American Institute of Physics.