Photolysis Production and Spectroscopic Investigation of the Highest Vibrational States in H (XΣ = 13, 14).

Rovibrational quantum states in the XΣ electronic ground state of H are prepared in the = 13 vibrational level up to its highest bound rotational level = 7, and in the highest bound vibrational level = 14 (for = 1) by two-photon photolysis of HS. These states are laser-excited in a subsequent two-photon scheme into FΣ outer well states, where the assignment of the highest (,) states is derived from a comparison of experimentally known levels in FΣ, combined with calculations of XΣ levels. The assignments are further verified by excitation of FΣ population into autoionizing continuum resonances, which are compared with multichannel quantum defect calculations. Precision spectroscopic measurements of the F-X intervals form a test for the calculations of ground state levels at high vibrational quantum numbers and large internuclear separations, for which agreement is found.