The ν3 band of 16O14N18O: Line positions and intensities. (November 2022) - Marinina, A.A.
Highlights: First detection of the ν3 band of the 16 O 14 N 18 O isotopologue centered at 1603 cm −1 . 1795 lines of the ν3 band of 16 O 14 N 18 O corresponding to 3487 transitions are assigned. Effective Hamiltonian parameters are fitted to the observed line positions. Effective dipole moment parameters are determined. List of the calculated line positions and intensities is presented. Abstract: The Fourier transform IR spectra of samples prepared by mixing two gaseous species 18 O2 / 14 N 16 O (1:2) have been recorded in the region of the ν3 band of nitrogen dioxide. The spectra contain the lines corresponding to the ν3 band of the 16 O 14 N 18 O isotopologue within the 1540–1640 cm −1 . In total 1795 lines of the ν3 band of this isotopologue were assigned with the rotational quantum numbers N and Ka up to 51 and 12, respectively, what corresponds to 3487 electron spin-rotation-vibration transitions. The overall measured set of the line positions was used to fit the effective Hamiltonian parameters. The fitted set of the parameters reproduces the observed line positions with an rms of 3.6 × 10 −3 cm −1 . A selected set of the measured line intensities was used to determine the effective dipole moment parameters describing the line intensities of the ν3 band. The rms deviation of the fit is 5.0%. It was found that the lines with the Δ Ka = ±1 are very weak compared to those with the Δ Ka =0. At attained sensitivity only few lines with the Δ Ka = ±1 were assigned. The measured line intensities lead to the small value of the dipole moment derivatives ratio | ( ∂ μ x / ∂ q 3 ) ( ∂ μ z / ∂ q 3 ) | ≈ 0.139 .