Publication Date:
2016-01-07
Description:
Double-resonance laser spectroscopy via the E F 1 Σ g + , v ′ = 6 , J ′ = 0 –2 state was used to probe the high vibrational levels of the B ′ ′ B ̄ 1 Σ u + state of molecular hydrogen. Resonantly enhanced multiphoton ionization spectra were recorded by detecting ion production as a function of energy using a time of flight mass spectrometer. New measurements of energies for the v = 51–66 levels for the B ′ ′ B ̄ state of H 2 are reported, which, taken with previous results, span the v = 46–69 vibrational levels. Results for energy levels are compared to theoretical close-coupled calculations [L. Wolniewicz, T. Orlikowski, and G. Staszewska, J. Mol. Spectrosc. 238 , 118–126 (2006)]. The average difference between the 84 measured energies and calculated energies is −3.8 cm −1 with a standard deviation of 5.3 cm −1 . This level of agreement showcases the success of the theoretical calculations in accounting for the strong rovibronic mixing of the 1 Σ u + and 1 Π u + states. Due to the ion-pair character of the outer well, the observed energies of the vibrational levels below the third dissociation limit smoothly connect with previously observed energies of ion-pair states above this limit. The results provide an opportunity for testing a heavy Rydberg multi-channel quantum defect analysis of the high vibrational states below the third dissociation limit.
Print ISSN:
0021-9606
Electronic ISSN:
1089-7690
Topics:
Chemistry and Pharmacology
,
Physics
