Photolysis production and spectroscopic investigation of the highest vibrational states in H₂ (x¹σ_g⁺ v = 13, 14)

Rovibrational quantum states in the X¹Σ_g⁺ electronic ground state of H₂ are prepared in the v = 13 vibrational level up to its highest bound rotational level J = 7, and in the highest bound vibrational level v = 14 (for J = 1) by two-photon photolysis of H₂S. These states are laser-excited in a subsequent two-photon scheme into F¹Σ_g⁺ outer well states, where the assignment of the highest (v,J) states is derived from a comparison of experimentally known levels in F¹Σ_g⁺, combined with ab initio calculations of X¹Σ_g⁺ levels. The assignments are further verified by excitation of F¹Σ_g⁺ 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 ab initio calculations of ground state levels at high vibrational quantum numbers and large internuclear separations, for which agreement is found.