Abstract
The Leiden Atomic and Molecular Database (LAMDA) collects spectroscopic information and collisional rate coefficients for molecules, atoms, and ions of astrophysical and astrochemical interest. We describe the developments of the database since its inception in 2005, and outline our plans for the near future. Such a database is constrained both by the nature of its uses and by the availability of accurate data: we suggest ways to improve the synergies among users and suppliers of data. We summarize some recent developments in computation of collisional cross sections and rate coefficients. We consider atomic and molecular data that are needed to support astrophysics and astrochemistry with upcoming instruments that operate in the mid- and far-infrared parts of the spectrum.
Highlights
Baryons constitute only ≈5% of matter in the Universe, the formation of stars and planets out of baryonic matter is a key astrophysical process
“Local Thermodynamic Equilibrium (LTE)” to refer to the high-density limit of molecular excitation. This usage ignores the original meaning of LTE in stellar astrophysics, where the internal states and molecular motions, and the ionization balance, molecular abundances, and the local source function of radiation at all frequencies are assumed to be in equilibrium at the same temperature
After reviewing current methods to calculate molecular collisional data (Section 2), this paper describes the actual status of Leiden Atomic and Molecular Database (LAMDA) (Section 3) and currently planned updates (Section 4)
Summary
Baryons constitute only ≈5% of matter in the Universe, the formation of stars and planets out of baryonic matter is a key astrophysical process. Radio astronomers commonly use the term “Local Thermodynamic Equilibrium (LTE)” to refer to the high-density limit of molecular excitation This usage ignores the original meaning of LTE in stellar astrophysics, where the internal states and molecular motions, and the ionization balance, molecular abundances, and the local source function of radiation at all frequencies are assumed to be in equilibrium at the same temperature. The Leiden Atomic and Molecular Database (LAMDA1,2 ; [1]) aims to provide astronomers with sets of input data for use in spectroscopic models of dilute gas. Twitter: @lamda_database http://cdms.de http://spec.jpl.nasa.gov while the High-resolution Transmission (HITRAN) molecular absorption database [5] extends through near- and mid-infrared wavelengths All three of these databases are curated and critically reviewed and the accuracy of radiative data rarely limits the analysis in quantitative astronomical spectroscopy. More recent calculations exist [29], but the difference with the posted rates is small
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