High-resolution absorption measurements of NH3 at high temperatures: 2100 - 5500

TL;DR

This study presents high-resolution infrared absorption spectra of ammonia at high temperatures, identifying numerous spectral lines and bands, including many observed for the first time, aiding in spectroscopic data for high-temperature conditions.

Contribution

The paper provides new high-temperature ammonia spectra and assigns many spectral lines for the first time, enhancing spectroscopic databases.

Findings

Identified 2308 spectral lines in ammonia at high temperatures.

Assigned 1755 lines to specific bands, many newly observed.

Improved spectral data for ammonia at elevated temperatures.

Abstract

High-resolution absorption spectra of \NH\ in the region 2100 - 5500 \cm\ at 1027 $^{\circ}$C and atmospheric pressure (1045 $\pm$ 3 mbar) are measured. An \NH\ concentration of 10\% in volume fraction is used in the measurements. Spectra are recorded in a high-temperature gas-flow cell using a Fourier Transform Infrared (FTIR) spectrometer at a nominal resolution of 0.09 \cm. The spectra are analysed by comparison to a variational line list, BYTe, and experimental energy levels determined using the MARVEL procedure. 2308 lines have been assigned to 45 different bands, of which 1755 and 15 have been assigned or observed for the first time in this work.