A size effect in the optical properties of powdered TiO2

The spectral reflectivity ρ in the region 0.36–2.1 μm and its change Δρ with irradiation by 30 keV electrons versus the average grain sizer _av in a TiO₂ (rutile) powder has been studied in the range 1–7.5 μm. It has been established that the dependence of ρ onr _av differs for different regions of the spectrum, but there is a common increase of ρ in the size range 2.5–4 μm. The value of Δρ after irradiation is also less in powders with this range of sizes. It has been shown that the dependence Δρ=f(r _av) with increasing electron fluence from 2·10¹⁵ to 4·10¹⁶ is strengthened for one band and weakened for another. Tomsk Polytechnic University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 41, No. 12, pp. 52–58, December, 1998.