Spectrum of ¹⁴N¹⁷O Isotopologue in the 5200–5550 cm⁻¹ Region: Spectroscopic Parameters for \({v}\) = 3 State

The absorption spectrum of the ¹⁴N¹⁷O molecule was recorded in the 5200–5550 cm⁻¹ range for the first time using a Bruker IFS-125M Fourier spectrometer with a spectral resolution of 0.0056 cm⁻¹. The analysis of the spectrum made it possible to detect 83 vibrational-rotational lines of the 3–0 band of the fundamental transitions in the X ²Π electronic state of the ¹⁴N¹⁷O molecule. For 29 resolved doublets, the positions and relative intensities of each component of a doublet are determined; the spectroscopic Λ-parameters are found. For the remaining 25 unresolved doublets, the positions and relative intensities of the doublet center are determined. The maximal rotational quantum number J was 24.5. The experimental line positions in the 3–0 band confirmed the calculated data given in the ExoMol database. The frequencies of recorded transitions weighted in accordance with experimental uncertainties have been processed, and the spectroscopic constants for the vibrational state \({v}\) = 3 have been determined. With the found spectroscopic constants, the rotational energy up to J = 30.5 in the vibrational state \({v}\) = 3 and the transition frequencies in 3–0 vibrational band for ²Π_1/2 and ²Π_3/2 electronic states were predictive calculated. The calculations showed agreement with the data given in the ExoMol database within a specified error.