NEW SPECTROSCOPIC ANALYSES OF THE A1-SIGMA+-X1-SIGMA+ BANDS OF LI-7-H1

The emission spectrum of 7LiH has been photographed in the ∼5200- to 8700-Å region and the previously taken spectrum in the ∼3400- to 5300-Å region has been reexamined. Bands of the A1Σ+-X1Σ+ electronic transition have been analyzed and the observed vibrational structure of the ground state has been extended from v″ = 5 to v″ = 12. Rotational levels significantly higher than those previously reported have been observed, and the higher rotational levels of v′ = 0, 1, and 2 of the A1Σ+ state were found to be anomalous. This anomaly is attributable to a breakdown of the rotational expansion for the anomalous A1Σ+ potential. A comparison of observed and theoretical relative band intensities reveals discrepancies presumably related to rotational shifts in transition probabilities, inaccuracies in the vibrational wavefunctions for low v′ of the A1Σ+ state, and/or inaccuracies in the A-X electronic transition moment. New RKR turning points have been calculated up to v″ = 12 of the X1Σ+ state. A cumulative list of all lines that have been identified belonging to the A1Σ+-X1Σ+ transition of 7LiH is included. © 1979.