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Carbon

1.59-0.66/''--''

Iron

1.51-1.63/''

Magnetite (Fe,04)

2.58-0.58/''

Copper

0.62-2.63/''

" Data from the Handbook of Chemistry and Physics, unless otherwise noted (~20-25°C).

h For solution densities from 1.035 to 1.189. ' For solution densities from 1.028 to 1.811. '' From Hinds (1982). '' From Huffman and Stapp (1973). ' At A 491 nm.

" Data from the Handbook of Chemistry and Physics, unless otherwise noted (~20-25°C).

h For solution densities from 1.035 to 1.189. ' For solution densities from 1.028 to 1.811. '' From Hinds (1982). '' From Huffman and Stapp (1973). ' At A 491 nm.

0.64 or 3.2), both i, and /,, fall from a maximum value at 6 0° as 9 increases. For smaller particles with a 0.8 (i.e., D A 0.26), initially falls as 0 increases but then rises as 0 approaches 180°, corresponding to backscattering; for these particles /, decreases only slightly from 0° to f80°. However, in all cases, i, and in, and hence the scattered light intensity Eq. (Z), show their maximum values at 6 0°, corresponding to forward light scattering.

The variation of scattered light intensity with 0 as typified by Fig. 9.19 clearly becomes more complex as the particle size increases, with sharp oscillations seen at a 10. However, recall that this is for a spherical homogeneous particle of a fixed size and for monochromatic light (e.g., a laser); when the particle is irregular in shape, these oscillations are far less prominent. This is also true for a group of particles of various sizes, that is, a polydisperse aerosol, where the overall scattering observed is the sum of many different contributions from particles of various sizes. Finally, nonmonochro-matic light and fluctuations in polarization also help to smooth out the oscillations.

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