Laser excitation spectroscopy of Ne₂ npπ Π_g Rydberg states observed in the afterglow of a corona discharge

Several Rydberg series attributable to transitions originating from the a ³Σ⁺_u metastable state of the neon dimer have been observed by laser excitation spectroscopy in the afterglow of a pulsed corona discharge. The n = 4-9 members of an npπ Π_g←a(0-0) series have been rotationally resolved and the upper states characterized. The probable multiplicity of the Π_g states is discussed. An unusual loss of intensity in the Q branches for the higher n member transitions and a weak perturbation between the υ= 1 vibrational level of the 5fσ ³Σ⁺_g state and the 6pπ Π_g, υ=0 level are also reported.