Binding of an electron by He and Xe

A recent theoretical paper [Guo, Wrinn, and Whitehead, Phys. Rev. A 40, 6685 (1989)] predicted the existence of ground-state bound negative ions of all the noble gases. In addition, experimental observations [Haberland, Kolar, and Reiners, Phys. Rev. Lett. 63, 1219 (1989)] suggest the existence of long-lived Xe-. We have examined the cases of He- and Xe-. For He-, we employed Levinson's theorem in conjunction with published and reliable theoretical e-He elastic-scattering phase-shift results. For Xe-, we employed electron-correlation theory in conjunction with multiconfigurational Hartree-Fock and variational bound-state calculations of total energies. We conclude that these ions do not exist in a ground configuration