PDS: The Planetary Atmospheres Node
Cover Page/Proposal Summary
ROSS-99 NRA 99-OSS-01
Date Due: 5/3/99
|
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: Atmosphere Structures and Particles |
| Major Equipment Proposal? No |
| Do you intend to submit an Education/Public Outreach (E/PO) proposal? No |
| Proposal Title: |
| Low Temperature Rate Coefficients for Outer Planet Atmospheric Photochemistry |
| Abbreviated Proposal Title: |
| Low Temperature Kinetics of Jovian Atmospheres |
| Principal Investigator: |
| Dr.
Gregory Paul Smith Molecular Physics Laboratory PS047 SRI International 333 Ravenswood Ave. Menlo Park, CA 94025-3493 Phone: 650-859-3496 Fax: 650-859-6196 E-mail: smith@mplvax.sri.com |
| Signature | Date |
| _____________________________________ | ____________ |
| Co-Investigators and Collaborators: | |||
| Type | Name | Affiliation | |
| Sci Co-I | Dr. David L. Huestis | SRI International | huestis@mplvax.sri.com |
Proposal Summary:
The atmospheric photochemistry of the outer planets and moons is controlled by hydrocarbon photolysis and radical recombination reactions. Reliable pressure-dependent rate constants are generally unavailable below 300K, but are needed to model hydrocarbon, methyl, nitrile, and CO concentrations and to derive atmospheric transport rates. The proposed research combines an RRKM theoretical approach with selected low temperature measurements, beginning with the key 2CH3=C2H6 reaction, to solve this modeling problem. The theoretical computations provide consistent rate parameters (vs. T and P) to describe all available data. Experiments will be conducted at 180K or lower with a laser photolysis - resonance enhanced multiphoton ionization (REMPI) detection technique to provide key low T data. Other important kinetics to be examined include steps leading to heavier polyynes and the nitrogen and oxygen kinetics relevant to Triton and Titan. The proposed research will contribute to the goals of the Planetary Atmospheres Program by providing kinetic models of the outer planets atmospheric photochemistry that properly describe the pressure and temperature dependences of the key reaction rates. Reliable values are not currently used or available, and are vital to proper interpretation of new and older atmospheric data, including the derivation of transport rates.
