The virtual electron state in a weakly polar molecule

The disappearance of a bound state of an electron is studied for a potential well surrounded by the tail of a dipole potential. The state is predominantly s wave in character. As the depth of the potential is reduced, the track of the bound-state pole in the complex momentum plane is found to continue into the lower half-plane without a gap at the origin, provided that the dipole moment is less than 1.19D.