The formation of antihydrogen by the charge transfer reaction

The cross sections for antihydrogen formation in the n = 1,2 and 3 levels from the Ps(1s) + (p) over bar --> e(-) + (H) over bar(nl) reaction are computed in the close-coupling approximation. A large L-2 basis of positron-hydrogen channels (28 states) is supplemented by the Ps(1s), Ps(2s) and Ps(2p) channels. The present results represent the most accurate calculations of this cross section yet undertaken. It is seen that the net cross section for antihydrogen formation decreases extremely rapidly as a function of increasing energy and beyond about 5 Ryd is essentially negligible.