In order to evaluate the simultaneous influence of a neighboring ion located at an arbitrary distance R and of free electrons on atomic bound states in high-density plasmas ($N_e$≳${10}^{23}$ ${\mathrm{cm}}^{\mathrm{-}3}$) we have suggested a transient molecule model that consists of a two-ion center surrounded by bound and free electrons. The Dirichlet boundary condition is laid down in such a way to make the total electrostatic potential constant over the entire molecular envelope and also to obtain the limit of two independent ion spheres or that of one united ion sphere when R→∞ or R→0, respectively. A closed form has been obtained for the interaction potential between bound and free electrons at the high-temperature limit. Energy levels and wave functions have been evaluated by diagonalizing the total Hamiltonian in the subspace of the lowest 40 molecular levels. A possible appearance of new spectral components and, in particular, a drastic reduction of the Stark effect are clearly shown.

• Received 21 February 1989

DOI:https://doi.org/10.1103/PhysRevA.40.1983