ExoMol line lists VIII: A variationally computed line list for hot formaldehyde

TL;DR

This paper presents a comprehensive, variationally computed line list for hot formaldehyde, covering millions of states and billions of transitions, improving spectral data accuracy for temperatures up to 1500 K.

Contribution

The authors developed the AYTY line list using empirical and ab initio methods, providing an extensive and accurate spectral database for formaldehyde at high temperatures.

Findings

Excellent agreement with laboratory spectra at room temperature.

Highlights limitations of existing HITRAN data.

Line list contains 10.3 million states and 10 billion transitions.

Abstract

A computed line list for formaldehyde, H$_2{}^{12}$C$^{16}$O, applicable to temperatures up to $T=1500$~K is presented. An empirical potential energy and {\it ab initio} dipole moment surfaces are used as the input to nuclear motion program TROVE. The resulting line list, referred to as \textit{AYTY}, contains 10.3 million rotational-vibrational states and around 10 billion transition frequencies. Each transition includes associated Einstein-$A$ coefficients and absolute transition intensities, for wavenumbers below 10~000 cm\(^{-1}\) and rotational excitations up to \(J=70\). Room-temperature spectra are compared with laboratory measurements and data currently available in the HITRAN database. These spectra show excellent agreement with experimental spectra and highlight the gaps and limitations of the HITRAN data. The full line list is available from the CDS database as well as at \url{www.exomol.com}.