Fordecades, NASA scientists had tried to match theinfrared emissions from carbon chemicals called Polycyclic aromatichydrocarbons (PAH) to a mysteriousinfrared glow released by certain stars. The scientists neverdid find theright match, but in the course of their research, they built up adatabase ofPAH signatures unmatched anywhere in the world.
NowNASA has put that PAH database online, opening up acornucopia of new information on these cosmologically, biologically andcommercially important carbon compounds.
"Initially,our hope was to help interpret theexperimental spectra, but over time, our computational capabilitiesmade itpossible to study molecules much larger than can be studied in thelaboratory," said Charles Bauschlicher Jr., a computational chemist at NASA?sAmes Research Center,in Moffett Field, Calif.
It'sthe world's largest collection of PAH infrared data,and the website contains nearly700 spectra of PAHs in their neutral and electrically chargedstates. Inaddition, it has tools to download PAH spectra ranging in temperaturefromminus 470 to 2,000 degrees Fahrenheit (243 to 1,093 degrees Celsius).Thanks tothese spectra, PAHs are now known to be abundant throughout theuniverse, butin exotic forms not readily found on Earth.
NASAtried to make the website user friendly forresearchers, and the interface visually resembles the Google homepage.One canexplore the database by charge, composition and spectral signatures.Toolsallow users to do analyses online. For example, spectra can be combinedtocreate a "composite" signature that can be compared directly to thespectrum of "unknown" material.
"PAHsin space are probably produced by carbon-rich,giant stars. A similar process produces soots here on Earth," saidLouisAllamandola, an astrochemist at NASA's Ames Research Center.
"Besidesastronomical applications," he said,"this PAH database and software can be useful as a new research toolforscientists, educators, policy makers, and consultants working in thefields ofmedicine, health, chemistry, fuel composition, engine design,environmentalassessment, environmental monitoring, and environmental protection."