SHAKEOVER PROBABILITY FOR ELECTRON CAPTURE Catalina Gonzalez, A. Godunov and J.H. McGuire Department of Physics, Tulane University, New Orleans, LA 70118-5698 The simple shakeover probabiity $P_S(B)$ for 1s-1s electron capture is formulated and evaluated at high collision velocities for several ion- atom interactions. Structure is found in $P_S(B)$ and a discontinuity in $dP_S/dB$ at $B=0$.