We have computed extinction cross sections for 0.5- and 1-μm volume-equivalent radius tetrahedral NH3 ice crystals with and without nonabsorbing foreign cores to determine how particle shape and composition affect the strength and shape of resonant absorption features at 9.4 and 26 μm. The peak of the resonance is shifted relative to that for spherical particles, the maximum is smaller (except for 1-μ particles at 9.4 μm), and the integrated strength of the absorption falls in approximate proportion to the volume fraction of the core. It appears that small (r < 5 μm) NH3 particles cannot be the principal component of the Jovian haze in the 300- to 500-mbar region.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science