A laser-induced fluorescence study of the jet-cooled nitrous oxide cation (N2O+)

Abstract

Laser-induced fluorescence and wavelength resolved emission spectra of the à (2)Σ(+) - X̃ (2)Π(i) electronic transition of the jet-cooled nitrous oxide cation have been recorded. The ions were produced in a pulsed electric discharge at the exit of a supersonic expansion using a precursor mixture of N(2)O in high pressure argon. Both spin-orbit components of the 0(0) (0) band were studied at high resolution and rotationally analyzed to provide precise molecular constants for the combining states. Emission spectra were obtained by laser excitation of the 0(0) (0), 2(0) (1), 3(0) (1), and 2(0) (2) absorption bands, providing extensive data on the ground state bending, stretching, and combination vibrational levels. These data were fitted to a Renner-Teller model including spin-orbit, anharmonic, and Fermi resonance terms. The observed energy levels and fitted parameters were found to be comparable to those in the literature predicted from an ab initio potential energy surface.

The N+ Formation Mechanism of Vibrationally Selected N2O+ Ions in the C2Σ+ State: A TPEPICO Imaging Study

“…As the N−O bond length almost remains in the dissociative photoionization process in the current excitation energy range, only 2D potential energy surfaces were paid attention to along the N−NO bond length and the N−N−O angle, while the N−O bond length was fixed at 1.209 Å. Based on the CASSCF wave functions, the full valence active space including the 4σ−9σ and 1π−3π orbitals was chosen, and 15 electrons for cations were active, i.e., CASSCF (15,12) for N 2 O + . In addition, vibrational frequency analyses of N 2 O + (C 2 Σ + ) were carried out at the TD-B3LYP/6-311G+(d) level using the Gaussian 16 program.…”

“…Both direct and indirect dissociation mechanisms have been verified in the decomposition process of N 2 O + in low-lying electronic states, due to complex and diverse interactions. The A 2 Σ + , B 2 Π, C 2 Σ + , and D 2 Π states of N 2 O + are all predissociative, except for a few lowest vibronic levels of A 2 Σ + . − ,− In the decomposition of N 2 O + (A 2 Σ + ) ions, NO + fragment was distinctly observed with bimodal rotational distributions along the NO + (X 1 Σ + ) + N­( 2 D) pathway, besides the lowest one of NO + (X 1 Σ + ) + N­( 4 S) . Likewise, the NO + (X 1 Σ + ) + N­( 2 D) pathway also dominated in the decomposition of N 2 O + (B 2 Π) ions, and the molecular bending was suggested to occur prior to the dissociation. , Very recently, we have conducted high-level ab initio calculations on N 2 O + in the A 2 Σ + and B 2 Π states, using the complete active space self-consistent field (CASSCF) and multireference second-order perturbation theory (CASPT2) .…”