ENERGY DIFFERENCE BETWEEN THE (NU=O,R=1) AND THE (NU=O,R=3) STATES OF H-2+, MEASURED WITH INTERSERIES MICROWAVE SPECTROSCOPY OF H2 RYDBERG STATES

We measure several transitions between specific Rydberg levels in the nearly degenerate (=0, R=1) n=28 and (=0, R=3) n=16 Rydberg manifolds of H2 with microwave spectroscopy. These measurements can be combined with calculations of the Rydberg fine structure to deduce the energy difference between the two states of the free H2 core. The result, E(=0, R=3)-E(=0, R=1)=288.859 00(8) cm-1, represents the most precise determination to date of any spectral property of the hydrogen molecular ion, to our knowledge. © 1990 The American Physical Society.