2-ELECTRON CAPTURE BY HE2-EVENT MODEL(, LI3+, AND B5+ IN THE INDEPENDENT)

We apply a single-channel distorted-wave approximation in conjunction with the independent-event model to calculate the double-capture cross sections by He2+, Li3+, and B5+ from neutral He. The capture probabil ities of the two electrons in two successive independent events are ca lculated by a single-channel distorted-wave approximation with realist ic screening charge parameters. Our T matrix has been evaluated analyt ically and therefore the present method is much simpler than other ava ilable rigorous calculations. Our results are compared with the measur ements and other calculations. It is found that the present method giv es fairly good agreement with the measurements.