Relativistic corrections to the dipole polarizability of the ground state of the molecular ion H₂^+

The recently reported precise experimental determination of the dipole polarizability of the H_2^+ molecular ion ground state [P.L. Jacobson, R.A. Komara, W.G. Sturrus, and S.R. Lundeen, Phys. Rev. A 62, 012509 (2000)] reveals a discrepancy between theory and experiment of about 0.0007a_0^3, which has been attributed to relativistic and QED effects. In present work we analyze an influence of the relativistic effects on the scalar dipole polarizability of an isolated H_2^+ molecular ion. Our conclusion is that it accounts for only 1/5 of the measured discrepancy.