The Photodetachment Cross Section of Ps^- and Elastic e^--Ps Scattering

Recently, we resolved the discrepancy in the photodetachment cross section of the positronium negative ion (Ps^-) between the prior Kohn variational calculation [1-3] and calculations using close-coupling wave functions [4-5]. Like the earlier calculations we evaluated this cross section in both the length and velocity forms . We are also considering the acceleration form of the cross section. For the e^-- Ps ¹P continuum wave function we used the Kohn and complex Kohn variational methods and for the ¹S bound-state wave function of Ps^- we used the Rayleigh-Ritz variational method. For elastic e^--Ps scattering below the Ps(n=2)-formation threshold we have computed ^1,3S and ^1,3P phase shifts using the Kohn, inverse Kohn, and complex Kohn variational methods with elaborate trial wave functions. We are currently computing ^1,3D phase shifts for e^--Ps scattering using these methods.



[1] S. J. Ward and M. R. C. McDowell, Europhys. Lett. 1, 167 (1986).

[2] S. J. Ward, Thesis, University of London, Unpublished (1986).

[3] S. J. Ward, J. W. Humberston and M. R. C. McDowell, J. Phys. B 30, 127 (1987).

[4] A. Igarashi, S. Nakazaki, and A. Ohsaki, Phys. Rev. A 61, 032710 (2000).

[5] A. Igarashi, I. Shimamura and N. Toshima, New J. Phys. 2, 17 (2000).