A predissociative triplet Rydberg state of the nitrogen molecule studied by near-infrared diode laser kinetic spectroscopy

A new 3Π-3Σ band was observed in a discharge plasma of the nitrogen molecule and helium using near-infrared diode laser kinetic spectroscopy. All the lines in this band exhibited line broadening of more than 0.1 cm−1. Rotational analysis revealed that the lower state of the transition was the E3Σg+(v=0) state of N2, which had already been studied in the D3Σ-E3Σ band. The term value and rotational constant suggested that the upper state is the G3Πu Rydberg state with an electron configuration of (N2+:X2Σ core)(3pπu). The line broadening is attributed to predissociation through a homogeneous interaction with a repulsive Πu state.