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Project Progress

The database of molecular spectroscopic parameters at http://vpl.ipac.caltech.edu/spectra/ contains a compilation of calculated and experimental linelists combined with a collection of empirical absorption cross-sections for specific molecules of interest to the VPL. The web pages provide spectral plots of the data, supplemental details about the molecule and the sources of information for the entries. The data are sorted by molecule, with separate files for each source. There are currently 62 molecules in the database; more are being added as information becomes available or upon request by VPL members. Data can be absorption cross sections, actual line parameter lists (of line positions, line intensities, lower state transition energies and broadening coefficients), or both. Each molecule may have available data from several different sources and sometimes at the same wavelength. The most common sources are infrared absorption cross-sections based on FTIR spectra recorded at the Pacific Northwest National Lab (PNNL), infrared line lists from the HITRAN (2004) database, and UV cross-sections from personal collections of VPL personnel. Other sources are listed specifically on the page for the individual molecule.

In the past year, all the molecules have been updated, in particular with HITRAN 2004 files and many UV/VIS data sets. Molecular hydrogen was added to the list. The actual data are not distributed via this website, but can be found on the HITRAN website, or requested by the astrobiology community via e-mail. The data reside on the VPL’s Planetmaker server for use with the VPL atmospheric modeling program. The information tables and spectral images created for the VPL website were also linked to the HITRAN website (http://cfa-www.harvard.edu/HITRAN/ ) at the request of the HITRAN manager L. S. Rothman, and the information we collated for interdisciplinary use is now also being used by the wider molecular spectroscopy community.

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