SSHADE-BandList, a novel database of absorption and Raman bands of solids

A critical missing database for the astrophysics and planetary science community using spectroscopy data is a compilation of band parameters (e.g., their position, width, intensity) of solids, for comparison with laboratory and field spectra, and observations of extraterrestrial objects. While many databases exist for gases [1], there's a scarcity for solids and liquids (mostly as tables in a few books and review papers), and the mode attributions of bands is not always clear.

The Solid Spectroscopy Hosting Architecture of Databases and Expertise (SSHADE) (https://www.sshade.eu/; [2]) is hosting data from 30 research groups in spectroscopy of solids across 15 countries. It provides spectra of solids relevant to astrophysics and planetary science (ices, minerals, carbonaceous matters, meteorites…) and over a wide range of wavelengths (mostly X-ray and VUV to sub-mm). Initial compilation of the “BandList” database [3], which is hosted in SSHADE, was publicly released in October 2021. It is an ongoing effort to provide the parameters (position, width, intensity, and their accuracy, shape) associated with electronic, vibration, and phonon bands of simple solids (ices, simple organics, minerals), in absorption and in Raman emission, and for different pressure and temperature. It also includes the solid composition and isotopic species involved, as well as the mode assignment (Fig. 1). The database is compilated from exhaustive review of the literature and laboratory measurements on well-characterized species, and as of early 2024, it consisted of over 1240 bands associated with 60 different band lists, including minerals and ices in different phases. An online search tool allows users to find specific bands or lists. Results can be displayed graphically using a spectra simulator with various unit and display options (Fig. 1), and data can be exported for further analysis. 

 

Figure 1. Absorption band list of natural calcite [4] from the SSHADE-BandList interface. (a) Bands displayed individually. (b) Sum of bands of whole band list.

Development of the SSHADE-BandList database interface and content will most likely last many years. This tool is expected to be crucial, aiding in the identification of unknown absorption bands in astrophysical and solar system objects, of best spectra to use in radiative transfer models, and in guiding the conception of new instruments.

 

References 

[1] Albert et al. (2020), Atoms 8(4)

[2] Schmitt et al. (2014), EPSC 2014

[3] Schmitt et al. (2022), EPSC 2022

[4] Leclef and Schmitt (2022), SSHADE/BANDLIST (OSUG Data Center)