An improved rovibrational linelist of formaldehyde, \spec{h212c16o}

TL;DR

This paper enhances the rovibrational line list of formaldehyde by analyzing existing data and adding new measurements, resulting in more accurate energy levels and an improved line list for astrophysical applications.

Contribution

The study provides a significantly improved and validated rovibrational line list for formaldehyde, combining literature data with new high-precision measurements using the MARVEL procedure.

Findings

Validated numerous transitions, increasing the reliability of energy levels.

Produced an extended and more accurate line list for formaldehyde.

Enhanced the accuracy of the ExoMol AYTY line list for hot formaldehyde.

Abstract

Published high-resolution rotation-vibration transitions of \spec{h212c16o}, the principal isotopologue of methanal, are analyzed using the MARVEL (Measured Active Rotation-Vibration Energy Levels) procedure. The literature results are augmented by new, high-accuracy measurements of pure rotational transitions within the ground, $\nu_3$, $\nu_4$, and $\nu_6$ vibrational states. Of the \nbNonRedTr\ non-redundant transitions processed, which come from \nbSr\ sources including the present work, \nbValTr\ could be validated, providing \nbEl\ empirical energy levels of \spec{h212c16o}\ with statistically well-defined uncertainties. All the empirical rotational-vibrational energy levels determined are used to improve the accuracy of ExoMol's AYTY line list for hot formaldehyde. The complete list of collated experimental transitions, the empirical energy levels determined, as well as the extended and improved line list are provided as Supplementary Material.