A dipole radiative rate for metastable antiprotonic helium is estimated using an existing Born-Oppenheimer wave function and the velocity form of the transition matrix element. This rate is 4.7 times faster than the one computed using the length form. It is suggested that the velocity form gives a rate that is easier to reconcile with experiment, as interpreted with accepted notions about exotic atom formation.

• Received 30 September 1993

DOI:https://doi.org/10.1103/PhysRevA.50.205