ExoMol molecular line lists XXX: a complete high-accuracy line list for water

TL;DR

The paper introduces POKAZATEL, a comprehensive high-accuracy line list for water vapor, covering extensive energy levels and transitions, crucial for astrophysical and atmospheric research.

Contribution

It provides the most complete and accurate water line list to date, combining experimental data with high-quality ab initio calculations for improved spectral modeling.

Findings

Contains over 5 billion transitions.

Achieves line position accuracy close to experimental precision.

Reproduces experimental intensities with ~1% accuracy.

Abstract

A new line list for H$_2$$^{16}$O is presented. This line list, which is called POKAZATEL, includes transitions between rotation-vibrational energy levels up to 41000 cm$^{-1}$ in energy and is the most complete to date. The potential energy surface (PES) used for producing the line list was obtained by fitting a high-quality ab initio PES to experimental energy levels with energies of 41000 cm$^{-1}$ and for rotational excitations up to $J=5$. The final line list comprises all energy levels up to 41000 cm$^{-1}$ and rotational angular momentum $J$ up to 72. An accurate ab initio dipole moment surface (DMS) was used for the calculation of line intensities and reproduces high-precision experimental intensity data with an accuracy close to 1 %. The final line list uses empirical energy levels whenever they are available, to ensure that line positions are reproduced as accurately as possible. The POKAZATEL line list contains over 5 billion transitions and is available from the ExoMol website (www.exomol.com) and the CDS database.