Spectroscopic study of the E 1Σ+g ‘‘shelf’’ state in 7Li2

The E 1Σ+g ‘‘shelf ’’ state of the 7Li2 molecule was investigated using a pulsed optical optical double resonance technique. The measurements cover the vibrational levels in the range 0≤v≤29 including the shelf region around 13≤v≤15. Molecular constants have been determined. Using an inverted perturbation approach, an effective potential energy curve has been generated within the adiabatic approximation whose quantum mechanical energy eigenvalues reproduce all the measured term values to within 0.113 cm−1 for the range 0≤v≤23 and 0≤J≤47.