The PNNL quantitative infrared database for gas-phase sensing: a spectral library for environmental, hazmat, and public safety standoff detection

Abstract

Pacific Northwest National Laboratory (PNNL) continues to expand its library of quantitative infrared reference spectra for remote sensing. The gas-phase data are recorded at 0.1 cm^-1 resolution, with nitrogen pressure broadening to one atmosphere to emulate spectra recorded in the field. It is planned that the PNNL library will consist of approximately 500 vapor-phase spectra associated with the U.S. Department of Energy’s environmental, energy, and public safety missions. At present, the database is comprised of approximately 300 infrared spectra, many of which represent highly reactive or toxic species. For the 298 K data, each reported spectrum is in fact a composite spectrum generated by a Beer’s law plot (at each wavelength) to typically 12 measured spectra. Recent additions to the database include the vapors of several semi-volatile and non-volatile liquids using an improved dissemination technique for vaporizing the liquid into the nitrogen carrier gas. Experimental and analytical methods are used to remove several known and new artifacts associated with FTIR gas-phase spectroscopy. Details concerning sample preparation and composite spectrum generation are discussed.