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 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 G³Π_u Rydberg state with an electron configuration of (N₂⁺:X²Σ core)(3pπ_u). The line broadening is attributed to predissociation through a homogeneous interaction with a repulsive Π_u state.