Infra‐red absorption, scattering, and total attenuation cross‐sections for water spheres

Calculations of the normalized absorption, scattering, and total attenuation cross‐sections of water spheres are presented for the wavelength range from 4 μ to 24 μ, at intervals of 1 μ for the wavelength interval from 4 μ to 10 μ, and at 2 μ intervals thereon to 24 μ. The calculations have been carried out to values of α (α is the ratio of sphere circumference to wavelength) of 30. For values of the Mie absorption parameter, k , greater than approximately 0·10, values of the normalized absorption cross‐section are shown to have a maximum which exceeds unity by an appreciable amount. In all instances, the values of the normalized scattering and total attenuation cross‐sections exceed unity over most ranges of α considered, the excess over unity being greater for small values of absorption. Some rough calculations are made comparing Mie absorption coefficients with those for bulk‐water absorption at the same wavelength.