The à ← X˜ (1+1)REMPI spectrum and high-level ab initio calculations of the complex between NO and N₂

Abstract

The results of two separate studies of the complex between NO and N₂ are reported. The (1+1) REMPI spectrum of the à ← X˜ transition of the complex between NO and N₂ is presented of improved quality over that reported previously, and the appearance of the spectrum is discussed. The results of high-level ab initio calculations [RCCSD(T)/aug-cc-pVQZ//QCISD/6-311+G(2d)] on the X˜² II state are also reported. The indications are that the NO moiety is more freely rotating in the complex than is N₂, and that a wide angular space is sampled in the zero-point energy level. The appearance of the REMPI spectrum suggests that the à ² Σ⁺ state is (close to) linear, and RCCSD(T)//QCISD calculations on the à state, using Rydberg-function-augmented basis sets, suggest that the lowest energy linear isomer is the ON． N₂linear orientation. It is clear, however, that the understanding of this complex, and its spectroscopy, is far from complete, and will be challenging.