Adiabatic method for positronic atoms and molecules

Abstract

The adiabatic separation of electronic and positronic degrees of freedom is proposed. The positronic charge in expressions for the potential energy is partitioned between the electronic and positronic Hamiltonians. This partitioning assures an acceptable electron density distribution around the positron. Our adiabatic method gives good values of binding energies and annihilation rates for model systems, in which the positron is weakly bound. On the other hand, it does not work well if the wave function contains a significant contribution of the positronium cluster.

Acknowledgements

This work was supported by Wrocław University of Technology. Thanks are due to Professor Henryk Stachowiak and Dr Edward Boroński for valuable discussions. The program Fudgit, used for analytically fitting of the effective potentials, has been written by Martin-D. Lacasse and is freely available from many public FTP archives. The authors are also grateful to MSc Karol Langner for carefully reading the manuscript.