J. Mitroy et G. Ryzhikh, THE FORMATION OF ANTIHYDROGEN BY THE CHARGE-TRANSFER REACTION, Journal of physics. B, Atomic molecular and optical physics, 30(10), 1997, pp. 371-375
The cross sections for antihydrogen formation in the n = 1,2 and 3 lev
els from the Ps(1s) + (p) over bar --> e(-) + (H) over bar(nl) reactio
n 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 extre
mely rapidly as a function of increasing energy and beyond about 5 Ryd
is essentially negligible.