Quantum chemistry calculation of excited three center systems:: Theoretical study of He2++H2 collisions

Close-coupling calculations of single (dissociative and nondissociative) and double electron capture cross sections in He2+ + H-2 collisions in the range of impact energies 0.5-25 keV/amu are presented and compared with experimental data. The calculations have been carried out at the Franck-Condon level and employing both ab initio expansions, in terms of three-center electronic functions, and the independent particle model approximation. We discuss the mechanisms of the processes and the validity limits of these treatments. (C) 2003 American Institute of Physics.