Ionization probes of molecular structure and chemistry. Progress report, January 15, 1993--January 14, 1994
The development of new techniques for the study of chemical systems is vital for progress in understanding commercially and environmentally important chemical reactions such as combustion, atmospheric ozone depletion, chemical etching in semiconductor manufacture, etc. The very high light flux obtainable from current tunable lasers enables the user to obtain a diagnostic response from molecules present in extremely small concentrations. It is the goal of this research to understand the photophysics of molecule-laser interactions and to devise new spectroscopic analysis techniques which tell us more about the molecules and enable their detection in difficult environments. With high powered pulsed lasers, an almost inevitable end product of the molecule-laser interaction is ionization of the molecule via the absorption of one or several photons. This provides an opportunity for detection because it is easy to collect and count ions. The challenge is to extract information from the ionization event, which typically does not convey the spectral signatures which allow detailed characterization. The author is presently exploiting the very high Rydberg states present just below the energy of each ionic state as referenced to the neutral ground state. By creating and field ionizing these Rydberg states, he is able to extract the states of the molecular ion from the continuum absorption. When he detects the resulting ion in a mass spectrometer, he calls the technique Mass Analyzed Threshold Ionization (MATI) spectroscopy. The information obtained from the experiment is equivalent to having an infrared spectrum of the ion responsible for each parent mass peak in a mass spectrometer sampling a mixture. The identity and structure of each species can be determined. The bulk of the effort in the last year has been involved with understanding the detailed mechanism of this technique and extending it to allow different light sources.
- Research Organization:
- State Univ. of New York, Stony Brook, NY (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-86ER13590
- OSTI ID:
- 10129525
- Report Number(s):
- DOE/ER/13590-13; ON: DE94007605; TRN: 94:003254
- Resource Relation:
- Other Information: PBD: Jan 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
RYDBERG STATES
IONIZATION
CARBON DIOXIDE
LASER SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
PROGRESS REPORT
MOLECULAR STRUCTURE
CHEMICAL REACTIONS
PHOTOCHEMISTRY
664200
400500
SPECTRA OF ATOMS AND MOLECULES AND THEIR INTERACTIONS WITH PHOTONS