Convergence of CI single center calculations of positron-atom interactions

Abstract

The Configuration Interaction (CI) method using orbitals centered on the nucleus has recently been applied to calculate the interactions of positrons interacting with atoms. Computational investigations of the convergence properties of binding energy, phase shift and annihilation rate with respect to the maximum angular momentum of the orbital basis for the e^+Cu and PsH bound states, and the e^+-H scattering system were completed. The annihilation rates converge very slowly with angular momentum, and moreover the convergence with radial basis dimension appears to be slower for high angular momentum. A number of methods of completing the partial wave sum are compared, an approach based on a Delta X_J = a/(J + 1/2)^n + b/(J + 1/2)^(n+1) form (with n = 4 for phase shift (or energy) and n = 2 for the annihilation rate) seems to be preferred on considerations of utility and underlying physical justification.

23 pages preprint RevTeX, 11 figures, submitted to PRA

References in corpus (2)

• Many-body theory of positron-atom interactions
• Energy and expectation values of the PsH system

Cited by in corpus (7)

• Positron-atom scattering using pseudo-state energy shifts
• Generating phase shifts from pseudo state energy shifts
• Positronic complexes with unnatural parity
• Second bound state of PsH
• The existence of a 2Po excited state for the e+Ca system
• Effective radius of ground- and excited-state positronium in collisions with hard walls
• Convergence of an s-wave calculation of the He ground state