Double Charge Transfer,He+++He

A model, previously discussed, in which electron correlation in helium is neglected, is used to calculate the double-charge-transfer cross section for ${\mathrm{He}}^{++}$ in He. The model yields a double-charge-transfer probability which is the product of two single-charge-transfer probabilities. The single-transfer probability is calculated by a Born approximation and a modified Born approximation. The one existing experiment is in satisfactory agreement with the latter.