Preferential population of n=2 states in low-energy Li3+-He collision: a molecular-state close-coupled treatment

The semi-classical, impact parameter, close-coupling method, in its molecul ar orbital form is employed to investigate the process of state selective c harge transfer from a two-electron target (He) to the incident bare nucleus of Li (i.e. Li3+) in the low-energy region. The effective binding of the a ctive electron in the quasi-diatomic molecule formed during the course of c ollision is obtained for the first time: in an ab initio way. The electron translation factor (ETF) modified Born-Oppenheimer wave function is generat ed to obtain the adiabatic molecular states of the quasi-molecule (LiHe)(3). A set of eight close-coupled . The equations is solved numerically to ob tain both the partial and total capture cross-sections at 0.5 less than or equal to E less than or equal to 5 keV amu(-1) cross-sections are compared with both the low-energy measurements and other available theoretical resul ts. The explicit n- and l-distributions of the capture cross-sections are a lso presented for the first time. Comparison is made with a recent calculat ion carried out in a similar manner for Li3+-H-2, another two-electron coll iding system. The structureless ion of Li, as expected, favors highly state selective population of the Li2+(2p) state in this collision. (C) 2000 Els evier Science B.V. All rights reserved.