Updated ro-vibrational MARVEL levels for ammonia 14NH3

Abstract

An extended list of empirical ro-vibrational energy levels for the ammonia isotopologue ¹⁴NH₃ is constructed using the MARVEL procedure. The final transition set includes 69710 experimental line positions from 97 experimental sources covering the wavenumber range below 18177 cm⁻¹ and rotational excitations up to $J=29$. The transition set incorporates 23844 newly collated experimental transitions extending the covered energy range beyond 7500 cm⁻¹, yielding 10753 empirical energy levels with uncertainties, an increase of 5817 from the previous MARVEL study. This MARVEL set is then used to reMARVELise the CoYuTe line list for ¹⁴NH₃, yielding a total of 641836 experimentally accurate line positions. The updated line list is available from www.exomol.com.