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Multiresonant Spectroscopy and the High Resolution Threshold Photoionization of Combustion Free Radicals.

DE2005850018

Publication Date	2003
Personal Author	Grant, E. R.
Page Count	22
Abstract	This report describes the results of a program of research on the thermochemistry, spectroscopy and intramolecular relaxation dynamics of the combustion intermediate, HCO. We prepare this radical from acetaldehyde as a photo-precursor in a differentially pumped laser-ionization source quadrupole mass spectrometer. Using a multiresonant spectroscopic technique established in our laboratory, we select individual rotational states and overcome Franck-Condon barriers associated with neutral-to-cation geometry changes to promote transitions to individual autoionizing series and state-resolved ionization thresholds. Systematic analysis of rotational structure and associated lineshapes provide experimental insight on autoionization dynamics as input for theoretical modeling. Extrapolation of series, combined with direct thresholdphotoelectron detection, yield precise ionization potentials that constitute an important contribution to the thermochemical base of information on HCO.
Keywords	Electronic spectroscopy Photoionization Cation thermochemistry Ionization Vibration Autoionization
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Purdue Research Foundation, Lafayette, IN.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200613

Multiresonant Spectroscopy and the High Resolution Threshold Photoionization of Combustion Free Radicals.

Multiresonant Spectroscopy and the High Resolution Threshold Photoionization of Combustion Free Radicals.
DE2005850018

Publication Date	2003
Personal Author	Grant, E. R.
Page Count	22
Abstract	This report describes the results of a program of research on the thermochemistry, spectroscopy and intramolecular relaxation dynamics of the combustion intermediate, HCO. We prepare this radical from acetaldehyde as a photo-precursor in a differentially pumped laser-ionization source quadrupole mass spectrometer. Using a multiresonant spectroscopic technique established in our laboratory, we select individual rotational states and overcome Franck-Condon barriers associated with neutral-to-cation geometry changes to promote transitions to individual autoionizing series and state-resolved ionization thresholds. Systematic analysis of rotational structure and associated lineshapes provide experimental insight on autoionization dynamics as input for theoretical modeling. Extrapolation of series, combined with direct thresholdphotoelectron detection, yield precise ionization potentials that constitute an important contribution to the thermochemical base of information on HCO.
Keywords	Electronic spectroscopy Photoionization Cation thermochemistry Ionization Vibration Autoionization
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Purdue Research Foundation, Lafayette, IN.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200613