title: Observations of the high vibrational levels of the B('')B̄ (1)Σ(u)(+) state of H2.
abstract: Double-resonance laser spectroscopy via the EF (1)Σg (+),v(')=6,J(')=0-2 state was used to probe the high vibrational levels of the B('')B̄ (1)Σu (+) 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('')B̄ state of H2 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)Σu (+) and (1)Πu (+) 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.
authors.affiliation: Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Chartrand
authors.affiliation: Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: W
authors.initials: W
authors.lastname: Duan
authors.affiliation: Physics and Astronomy Department, University of Mount Union, Alliance, Ohio 44601, USA.
authors.forename: R C
authors.initials: RC
authors.lastname: Ekey
authors.affiliation: Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010, USA.
authors.forename: E F
authors.initials: EF
authors.lastname: McCormack