Electron-impact double ionization of B+

Time-dependent close-coupling and time-independent distorted-wave methods are used to calculate the electron-impact double-ionization cross section for the 1s22s2 ground configuration of the B+ atomic ion. The direct double-ionization cross section is calculated using the non-perturbative close-coupling method between the direct double-ionization threshold of 63.1 eV and the 1s ionization threshold of 218.4 eV. The indirect single ionization-autoionization cross section is calculated using the perturbative distorted-wave method between the 1s ionization threshold of 218.4 and 750 eV. The double-ionization cross section calculated using the two methods is compared with a crossed-beam experiment over the entire energy range.