An effect of "scattering by absorption" observed in near-infrared properties of nanoporous silica

被引:30
作者
Dombrovsky, Leonid [1 ]
Lallich, Sylvain [2 ]
Enguehard, Franck [3 ]
Baillis, Dominique [2 ]
机构
[1] Joint Inst High Temp, Moscow 111116, Russia
[2] CNRS, UMR 5008, Ctr Therm Lyon, Inst Natl Sci Applquees, F-69621 Lyon, France
[3] CEA Le Ripault, F-37260 Monts, France
基金
俄罗斯基础研究基金会;
关键词
RADIATIVE PROPERTIES; LIGHT-SCATTERING; OPTICAL-CONSTANTS; QUARTZ; MEDIA;
D O I
10.1063/1.3374473
中图分类号
O59 [应用物理学];
学科分类号
摘要
The obtained spectroscopic data for absorption and scattering characteristics of nanoporous silica in the wavelength range from 0.25 to 7 mu m are analyzed on the basis of the Mie theory. It is shown that aggregates of primary nanoparticles are responsible for relatively high scattering in the short-wave range from 0.25 to 1.4 mu m. But the presence of the aggregates and micron-size cracks in the samples cannot explain unusual behavior of scattering in the long-wave part of the spectral range. The attention of the authors is focused on understanding of strong scattering peaks observed at exactly the same wavelengths as the infrared absorption peaks of bulk silica: at lambda = 2.9, 5.3, and 6.1 mu m. The known physical effect of "scattering by absorption" is considered as a source of these scattering peaks. It means that absorption centers are assumed to be not uniformly distributed in the nanoporous matrix but collected in some micron-size regions. The estimates based on this hypothesis are supported by the fact that near-infrared absorption peaks are produced by silanol groups which may be nonuniformly distributed in the hydroxylated nanoporous silica. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3374473]
引用
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页数:8
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