We have calculated polarizabilities (${\alpha }_1$, ${\beta }_1$, ${\gamma }_1$, ${\alpha }_2$, ${\beta }_2$, and ${\gamma }_2$) of ${\mathrm{Ps}}^{-}$ by the pseudostate method. These parameters can be used to calculate Rydberg states of ${\mathrm{Ps}}^{-}$ in the presence of an external electron with high quantum numbers $N$ and $L$. They are also of importance in a system containing ${\mathrm{Ps}}^{-}$ bound to a proton [PsH] and also Rydberg states of ${\mathrm{Ps}}_2$.

• Received 27 April 2007

DOI:https://doi.org/10.1103/PhysRevA.75.062510