Single-electron capture

In accordance with previous investigations [8,9], Aese experiments have shown a quite different behaviour for N (ls )than for other multicharged ions such as the isoelectronic ion [10. The single-electron capture process has been shown to be dominant on the n = 3 levels and in particular on the 3s level for collision energies lower than 50 keV. A high probability of double capture has also been observed characterized by an intense peak at X = 76.5 nm attributed to the 2s > 2s 2p P transition [4,5,7]. Furthermore,... 

A complete theoretical treatment of the + He collision should therefore take into account, first the single-electron capture process from the ground state entry channel... 

Fig. 2. a, b, c. Non-adiabatic radial coupling matrix elements for the states of single-electron capture. 

Fig. 3. Rotational coupling matrix element between the ll (N (3p) + He (ls)) state and the states of single-electron capture.

The potential energy curves of the Z" and 11 states are presented in Fig. 4. They show four avoided crossings in the range 15.0-10.0 a.u.] between the entry channel, the state corresponding to N +(ls2p3s) -t- He )and the three states of single-electron capture N +(ls2s3/) L-i-He+). 

SINGLE-ELECTRON CAPTURE PROCESS FROM THE GROUND STATE... 

Table 4. Single-electron capture cross-sections on the n = 3 levels (in 10 cm ). (For comparison with Dijkkamp results, the collision energy is given in parenthesis...

Partial cross-sections of single-electron capture. 

Table 5. Values of the single-electron capture cross-sections for the and states (in 10" cm ).

TABLE 2. Comparison of asymptotic energy values with experimental [13] (single-electron capture levels) and theoretical data [17] (double-electron capture levels) (ina.u)... 

A complete theoretical treatment of the + He collision should therefore take into account, first the single-electron capture process from the ground state entry channel N (ls ) S -I- He(ls ) S and also from the metastable level NP (ls2s)-1- He(ls ) in order to take eare of the fraction of metastable N ion in the incident beam, as well as the double-eleetron capture process from both ground and metastable ions. 

SINGLE-ELECTRON CAPTURE PROCESS FROM THE GROUND STATE N5+(Is2)1s + He(ls2) S... 

Fig. 4.1. CDW-EIS cakulatioas of a for protons and antiprolons on helium by Fainstein et al. [4.5 are shown as soUd curves. The dashed curve shows the single electron capture cross section for p on helium as measured by Rudd et al. [4.41] and Shah and Gilbody [4.19]. The hatched area above the energy axis indicates velocities around that of the target elections.

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