Near-Infrared Diode Laser Spectroscopy of the Nitrogen Molecule in Rydberg State: Analysis of thec1Πu−a″1Σg+,v= 1–0 Band

A new singlet-singlet absorption band between Rydberg states of the nitrogen molecule was studied by near-infrared diode laser spectroscopy in the 1.3 μm region. An analysis was made for the band to establish line assignments and determine molecular parameters for both the lower and the upper vibronic states. As a result of the analysis, this band was assigned to thec1Πu–a″1Σg+, v = 1–0 band. The anomaly of the Λ-type doubling structure in thec1Πu(v= 1) state was discussed in connection with the interaction with theb′1Σu+(v = 4) state. The predissociation in thec1Πu(v= 1) state was also discussed relating with the line broadening observed.