Description of ionization in the molecular approach to atomic collisions
- Laboratoire des Collisions Atomiques, Centre de Physique Theorique et Modelisation, URA 1537 du CNRS, Universite de Bordeaux I, 351 Cours de Liberation, 33405 Talence Cedex (France)
- Departamento de Quimica, C-IX, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain)
Molecular treatments of atomic collisions have traditionally been restricted to low nuclear velocities because of their failure to reproduce the fall of the capture cross sections at higher velocities. The limitation has recently been seen to be due to their description of ionizing processes. This feature is shown here to be a general one for multicharged ion-atom collisions. Its origin and characteristics are described and illustrated for the prototypical Li{sup 3+}+H(1s) reaction. Ionization appears as a result of the inertia of the electron cloud to adiabatically follow the nuclear motion. This gives rise to nonadiabatic transitions, which represent an ionizing flux whenever the nuclear velocity is high enough that the energy of the traveling molecular orbitals involved is positive in both moving atomic reference frames. Two strongly connected mechanisms appear, corresponding to the relative translational and rotational nuclear motions. Because of the finiteness of the basis, these mechanisms terminate with unphysical trapping effects. While interesting {ital per se}, knowledge of these features is also useful with respect to improving molecular treatments of atomic collisions with the addition of pseudostates. {copyright} {ital 1996} {ital The American Physical Society}
- OSTI ID:
- 432516
- Journal Information:
- Physical Review A, Vol. 55, Issue 1; Other Information: PBD: Jan 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
H type of hidden crossings in atomic collisions involving highly charged ions
Triple-center treatment of electron transfer and ionization in He/sup 2 +/-H and p-He/sup +/ collisions