Exomol molecular line lists VI: A high temperature line list for Phosphorus Nitride

TL;DR

This paper presents comprehensive high-temperature rotational-vibrational line lists for phosphorus nitride isotopologues, enabling accurate spectral simulations up to 5000 K, crucial for astrophysical and planetary research.

Contribution

The authors developed and validated extensive line lists for $^{31}$P$^{14}$N and $^{31}$P$^{15}$N using empirical and ab initio methods, extending spectral data to high temperatures.

Findings

Line lists contain nearly 700,000 lines each.

Root-mean-square error of 0.004 cm$^{-1}$ in reproducing experimental data.

Applicable for temperatures up to at least 5000 K.

Abstract

Accurate rotational-vibrational line lists for $^{31}$P$^{14}$N and $^{31}$P$^{15}$N in their ground electronic states are computed. The line lists are produced using an empirical potential energy curve obtained by fitting to the experimental transition frequencies available in the literature in conjunction with an accurate, high level \textit{ab initio} dipole moment curve. In these calculations the programs DPotFit and LEVEL~8.0 were used. The new line lists reproduce the experimental wavenumbers with a root-mean-square error of 0.004~cm$^{-1}$. The line lists cover the frequency range 0--51000 cm$^{-1}$, contain almost 700~000 lines each and extend up to a maximum vibrational level of $v$=66 and a maximum rotational level of $J$=357. They should be applicable for a large range of temperature up to, at least, 5000~K. These new line lists are used to simulate spectra for PN at a range of temperatures and are deposited in the Strasbourg data centre. This work is performed as part of the ExoMol project.