00-035

Cover Page/Proposal Summary

ROSS-99    NRA 99-OSS-01

Date Due: 5/3/99

NASA PROCEDURE FOR HANDLING PROPOSALS

This proposal shall be used and disclosed for evaluation purposes only, and a copy of this Government notice shall be applied to any reproduction or abstract thereof. Any authorized restrictive notices that the submitter places on this proposal shall also be strictly complied with. Disclosure of this proposal for any reason outside the Government evaluation purposes shall be made only to the extent authorized by the Government.

Proposal Type: New Proposal

Proposal Category: Laboratory

Major Equipment Proposal? No

Do you intend to submit an Education/Public Outreach (E/PO) proposal? No

Proposal Title:
Electron Impact Cross Sections for Atoms and Molecules of Planetary Interest

Abbreviated Proposal Title:
Electron Impact Cross Sections

Principal Investigator:
Dr. Sandor Trajmar
Atomic and Molecular Collisions Research Element, Earth and Space Sciences, MS 183-601
Jet Propulsion Lab.
4800 Oak Grove Drive
Pasadena, CA 91109-8099
Phone: 818-354-2145   Fax: 818-393-4605   E-mail: Sandor.Trajmar@jpl.nasa.gov

SignatureDate
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Co-Investigators and Collaborators:
Type    Name    Affiliation    E-mail
Sci Co-I   Dr. Isik Kanik   JPL   ikanik@pop.jpl.nas a.gov
Sci Co-I   Dr. Murtadha A. Khakoo   CalState   mkhakoo@exch ange.fullerton.edu
Sci Collab   Dr. Joseph M. Ajello   JPL   jajello@jpluvs.jp l.nasa.gov


Proposal Summary:

In planetary atmospheres, stellar atmospheres and diffuse molecular clouds, a dominant energy mechanism for energy transfer is electron collision processes with neutral species leading to UV radiation. However, a fundamental limitation in obtaining accurate composition and energy deposition information from spacecraft observations (i.e. emission measurements) is the accuracy of the cross sections used in the data reduction algorithms (models), many of which are known to absolute accuracies of only +/- 25-50%. It is only recently with the technical development of the Electron Collision Processes Laboratory at JPL that a high level of accuracy (7-12% depending on the signal statistics) in electron-impact excitation cross section measurements for at low-energy region has become possible and electron-impact-induced excitation processes can be studied with a high level of confidence. To answer the need for electron-impact excitation cross sections for species of importance in planetary atmospheres with better accuracy for use in modeling ground and spacecraft observations of the planetary atmospheric spectra, we have established a collaborative research program between the Jet Propulsion Laboratory (JPL) and California State University at Fullerton (CSUF). In this three-year renewal proposal, we propose:(a) To extend our earlier cross section measurements for H2, from the intermediate energy range to the low, near threshold energy region (<20 eV)and measure the electron-impact excitation cross sections of the (b3Su+, a3Sg+, c3Pu, B1Su+, and C1P )states in low, near threshold energy region. (b)To measure the electron-impact excitation cross sections of SO2, O and O2 in the low, near threshold (0.5 eV above the threshold) energies, for the first time (8-20 eV). (c)To calibrate the electron excitation cross sections utilizing a novel electron TOF technique. These species represent the most important atomic and molecular species in the Jovian planetary system.