Positronium formation in positron endash alkali-metal-atom collisions: An optical potential approach

Integral and differential cross sections for the Ps-formation channel for e+endash alkali-metal-atom collisions are calculated, with considerable success, by means of a model optical potential. The atomic targets discussed here are Li, Na, and K. The potential is obtained without empirical parameters via a global modeling of the dynamical polarization potential and of the short-range correlation forces, with the use of generalized damping functions. The absorption part of the potential is obtained by means of a dispersion relation. We present here a full account of this simple and promising technique. copyright 1996 The American Physical Society