Infrared diode laser spectroscopy of O₂—N₂O van der Waals complex in the ν₁symmetric stretch region of N₂O

Abstract

The rovibrational spectrum of O 2 -N 2 O van der Waals complex is measured in the ν 1 symmetric stretch region of N 2 O monomer using a tunable diode laser spectrometer. The complex is generated by a slit-pulsed supersonic expansion with gas mixtures of O 2 , N 2 O, and He. Both aand b-type transitions are observed. The effective Hamiltonian for an open-shell complex consisting of a diatomic molecule in a 3 Σ electronic state and a closed-shell partner is used to analyze the observed spectrum. Molecular constants in the vibrationally excited state are determined accurately. The band-origin of the spectrum is determined to be 1284.7504(25) cm −1 , red-shifted from that of the N 2 O monomer by ∼ 0.1529 cm −1 .

Structure and Abundance of Nitrous Oxide Complexes in Earth’s Atmosphere

“…Qian et al recorded rotationally resolved infrared spectra of O 2 –N 2 but could not arbitrate between two different distorted slipped-parallel structures . Song et al also recorded rotationally resolved infrared spectra of O 2 –N 2 but only determined the intermolecular distance and not the intermolecular angles . Very recently, we showed that the distorted slipped parallel structure of O 2 –N 2 O shown in Figure is the global minimum and is ∼0.3 kJ mol –1 lower in energy than the alternative local minimum slipped parallel structure (where the O 2 subunit is distal to the O of N 2 O) .…”

“…42 Song et al also recorded rotationally resolved infrared spectra of O 2 −N 2 but only determined the intermolecular distance and not the intermolecular angles. 43 Very recently, we showed that the distorted slipped parallel structure of O 2 −N 2 O shown in Figure 1 is the global minimum and is ∼0.3 kJ mol −1 lower in energy than the alternative local minimum slipped parallel structure (where the O 2 subunit is distal to the O of N 2 O). 32 The structure of the Ar−N 2 O complex has been extensively studied by rotational resonance and rotationally resolved vibrational spectroscopy.…”

“…Note that the calculated vibrational–rotational coupling terms for O 2 –N 2 O were unreasonable and are therefore not shown. See text for details c Reference . d Reference . e Reference . f Reference . g Reference . h Reference . i Reference . j Reference . k Reference . l Reference . m Reference . …”

The structure of the O2–N2O complex

“…Previous high-resolution infrared spectra of the O 2 -N 2 O complex are consistent with a planar structure. 13,14 If we assume only minor geometric changes upon complexation, then the structure of O 2 -N 2 O can be described in terms of the Jacobi coordinates R cm , θ 1 , and θ 2 , as shown in Figure 1.…”