Determination of the dipole polarizabilities of H-2(+)(0,0) and D-2(+)(0,0) by microwave spectroscopy of high-L Rydberg states of H-2 and D-2

The fine-structure intervals separating n=9 and 10, L=5-8 Rydberg levels of H-2 and D-2, bound to the v=0, R=0 ground states of H-2(+) and D-2(+), are measured with microwave spectroscopy and used to determine the isotropic dipole polarizabilities of both ion ground states. The results alpha(s)(H-2(+))=3.1659(8)a(0)(3) and alpha(s)(D-2(+))=3.0667(8)a(0)(3) are more precise than existing theoretical predictions, and their explanation will pose a substantial challenge to the theory of this fundamental ion. [S1050-2947(97)51212-1].