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VPL Molecular Spectra Search Engine

The Virtual Planetary Laboratory Molecular Spectra Search Engine is a search engine to query the molecular spectroscopic database HITRAN 2008 and display plots of line intensity versus wavelength (or wavenumber) within a user specified wavelength (or wavenumber) range. The HITRAN database contains high resolution spectroscopic data which has several orders of magnitude range in wavenumbers. Static plots of this data do not give enough fine resolution details. A major advantage of the VPL search engine is that by specifying wavelength (or wavenumber) ranges, it allows you to zoom in and zoom out to identify features of interest.

The y-axis is line intensity S ( in units of cm^(-1)/(molecule cm^(-2)) ).
The x-axis is wavelength (in units of microns) or wavenumber (in units of cm^(-1)).

For further details see the book by Goody and Yung listed below. For more on line intensity see Chapter 3. For discussion of specific molecules see Chapter 5. For how to relate line intensity to observed spectra see Chapter 6.


  1. Atmospheric Radiation
    R. M. Goody and Y. L. Yung
    Oxford University Press 1989

  2. HITRAN documentation

Useful links: