Electron affinity of positronium embedded in Debye plasma

The effect of environment like that of a plasma on the ground state energy of positronium minus ion (Ps(-)) has been estimated variationally using multi-term correlated basis sets. Debye model has been applied to include the plasma screening effect in the interaction energy between two charge particles. The electron affinity of positronium is estimated for different Debye screening parameters and is found to decrease monotonically with increasing screening. (C) 2003 Elsevier Science B.V. All rights reserved.