Polarizability of the ground state of the hydrogen molecular ion

The dipole polarizabilities of the ground states of the ions H-2(+) and D-2 (+) have been calculated without making use of the Born-Oppenheimer approxi mation. Instead, the ions were treated as three-body systems whose ground s tates are spherically symmetric, and the polarizabilities were calculated u sing second-order perturbation theory with intermediate p pseudostates. The wave functions of both the ground and intermediate states are taken to be of generalized Hylleraas form, but it is necessary to use quite high powers of the internuclear coordinate to simulate the localized motion of the nuc lei; We obtain good values of;the groundstate energies, and report values o f the polarizabilities, to be compared with recent measurements. [S1050-294 7(99)02001-6].