ATOMIC-ELECTRON CAPTURE IN THE PRESENCE OF A NARROW NUCLEAR-RESONANCE- AR-40(P,P)AR-40 REACTION

Electron capture in close, energetic collisions between protons and Ar atoms is studied. As the proton energy is varied across the 1859.7-ke V Ar-40(p,p)Ar-40 elastic nuclear resonance at a fixed deflection angl e of 60-degrees, a dip of about 27% in the atomic-electron-capture pro bability is found, demonstrating the influence of the nuclear process on the atomic-charge exchange. The effect is very large considering th at the similar dip found in the probability for scattering the proton without capture is only about 37%. A systematic comparison with previo usly reported capture probabilities for other elastic reactions has be en made.