ExoMol line lists -- XXII. The rotation-vibration spectrum of silane up to 1200 K

TL;DR

This paper presents a comprehensive variational line list for silane (SiH4) applicable up to 1200 K, covering millions of transitions and validated against experimental data, significantly aiding astrophysical and atmospheric research.

Contribution

The study provides the first extensive, temperature-dependent line list for silane with nearly 63 billion transitions, using a refined potential energy surface and high-level ab initio calculations.

Findings

Line list contains 62.7 billion transitions between 6.1 million energy levels.

Accurately reproduces weaker spectral features compared to experimental data.

Available for use in astrophysical and atmospheric modeling.

Abstract

A variationally computed $^{28}$SiH$_4$ rotation-vibration line list applicable for temperatures up to $T=1200\,$K is presented. The line list, called OY2T, considers transitions with rotational excitation up to $J=42$ in the wavenumber range $0$--$5000\,$cm$^{-1}$ (wavelengths $\lambda> 2\,\mu$m). Just under 62.7 billion transitions have been calculated between 6.1 million energy levels. Rovibrational calculations have utilized a new `spectroscopic' potential energy surface determined by empirical refinement to 1452 experimentally derived energy levels up to $J=6$, and a previously reported \textit{ab initio} dipole moment surface. The temperature-dependent partition function of silane, the OY2T line list format, and the temperature dependence of the OY2T line list are discussed. Comparisons with the PNNL spectral library and other experimental sources indicate that the OY2T line list is robust and able to accurately reproduce weaker intensity features. The full line list is available from the ExoMol database and the CDS database.