Experimental observation of the ν1+3 ν3 combination bands of 16O14N18O and 18O14N18O in the near infrared spectral region

S Chandran; J Orphal; A A Ruth

doi:10.1016/j.heliyon.2024.e24853

Experimental observation of the ν₁+3 ν₃ combination bands of ¹⁶O¹⁴N¹⁸O and ¹⁸O¹⁴N¹⁸O in the near infrared spectral region

Heliyon. 2024 Jan 24;10(3):e24853. doi: 10.1016/j.heliyon.2024.e24853. eCollection 2024 Feb 15.

Authors

S Chandran¹, J Orphal², A A Ruth¹

Affiliations

¹ School of Physics & Environmental Research Institute, University College Cork, Cork, Ireland.
² Division 4 "Natural and Built Environment", Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, 76131, Karlsruhe, Germany.

Abstract

The first observation of the ν₁+3ν₃ combination band of the nitrogen dioxide isotopologue ¹⁶O¹⁴N¹⁸O is presented. The band was measured using Fourier-Transform Incoherent Broad-Band Cavity Enhanced Absorption Spectroscopy (FT-IBBCEAS) in the region between 5870 cm^-1 and 5940 cm^-1. To confirm the assignment, the band was simulated using a standard asymmetric top Watson Hamiltonian using extrapolated rotational and centrifugal distortion constants. Furthermore, the first experimental observation of the ν₁+3ν₃ band of the ¹⁸O¹⁴N¹⁸O isotopologue is also reported. The positions of ro-vibrational lines of the ν₁+3ν₃ band of the naturally most abundant isotopologue ¹⁶O¹⁴N¹⁶O were used for wavenumber calibration of line positions.

Keywords: Cavity enhanced absorption spectroscopy; Combination bands; FT-IBBCEAS; Fourier transform (FT); Isotopologues; Near infrared (IR); Nitrogen dioxide.