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Scattering by a coated sphere: Test values Parent topic
 
Table 2. Results of calculations of the absorption efficiency, Qa, of coated spheres: water shell on "carbon" core. Column λ contains the wavelength of light in vacuum, column m2 contains the complex refractive index of water, as reported by Fenn RW and Oser 1965 (their Table II). Column xc and column xs contain the relative sizes, of the core and shell, respectively. The ratio of xs to xc equals 17. The shell thickness, relative to the shell radius of rs = 0.368 µm, equals 0.9411764. The refractive index of the core (relative to that of the surrounding non-absorbing medium) is m2 = 1.59 − i 0.66 (as given by Fenn RW and Oser). Column Qa (FO1965) contains the absorption efficiency, Qa, obtained by Fenn RW and Oser 1965 (their Table I, column b/a = 17, a = 0.368). Column Qa (CSS) contains Qa obtained with the MJC Light Scattering Calculator for Coated Sphere (CSS). Note that the absorpion efficiency values tend to diverge as the relastive particle size increases (yellow colored cells). When the particle size increases, the calculations involve an increasingly larger number of terms, suggesting that the convergence problems in the Fenn RW and Oser program might have been the source of this divergence. See also Table 1, where results for much greater particle sizes obtained with CSS and another independently developed modern program, agree to 7 decimals.
 
λ, µm m2 xc xs Qa (FO1965) Qa (CSS)
1.35 1.327 - i 3.223e-5 1.7176471 29.2 0.0121 0.0189836
1.5 1.323 - i 0.316e-3 1.5411765 26.2 0.0493 0.04201250
2.0 1.304 - i 0.111e-2 1.1588235 19.7 0.0851 0.09237532
3.0 1.409 - i 0.1747 0.7705882 13.1 1.1846 1.184963
3.2 1.473 - i 0.1690 0.7235294 12.3 1.1910 1.191040
3.4 1.438 - i 0.1690 0.6823529 11.6 1.0153 1.209690
4.5 1.342 - i 0.0160 0.5117647 8.7 0.5022 0.496285
5.47 1.297 - i 0.0146 0.4235294 7.2 0.3734 0.374065
6.0 1.311 - i 0.1011 0.3882352 6.6 1.1312 1.132952
7.0 1.327 - i 0.0451 0.3294117 5.6 0.7384 0.737012
10.0 1.208 - i 0.0560 0.2294117 3.9 0.5757 0.571803


CITATION:
Jonasz M. 2009. Scattering by a coated sphere: Test values (www.tpdsci.com/Tpc/ScaCtSphTestVal.php). In: Top. Part. Disp. Sci. (www.tpdsci.com).
HISTORY:
Published: 15-Apr-2009
Modified: 29-Jun-2009
Peer-reviewed: PENDING
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