  The effect of plasma screening on the electronic and vibrational properties
of the H2+ molecular ion was analyzed within the Born-Oppenheimer
approximation. When a molecule is embedded in a plasma, the plasma screens the
electrostatic interactions. This screening is accounted for in the
Schr\"odinger equation by replacing the Coulomb potentials with Yukawa
potentials that incorporate the Debye length as a screening parameter.
Variational expansions in confocal elliptical coordinates were used to
calculate energies of the 1ssg and the 2psu states over a range of Debye
lengths and bond distances. When the Debye length is comparable to the
equilibrium bond distance, the plasma screening reshapes the potential energy
curve. Expectation values, dipole polarizabilities and spectroscopic constants
were calculated for the 1ssg state.
