ANNIHILATION RATE IN PS- AND PROPERTIES OF 2-ELECTRON IONS

The expectation values of the various geometric parameters were determined for the ground state of the Ps- ion. The evaluated (e+, e-) pair annihilation rate in Ps- is approximately 2.086 121 x 10(9) s-1. The mass dependence of a number of geometric parameters for symmetric negative ions such as X- X-Z+ where m(X) less-than-or-equal-to m(Z) was also studied. It is shown that all presented geometrical parameters have a smooth form of the mass dependence.