tokens: ), the inner radius of the disc is 0.06 au. Additionally, the disc is in hydrostatic equilibrium in the vertical direction and its density profile ρ( r , θ) is given by the equation from Dullemond ( 2000 ): Here, Σ 0 is the superficial density at the outer edge of the disc, R 0 is the external radius of the disc and H ( r ) is the disc scaleheight. The last variable is defined from the self-irradiated passive disc proposed by Chiang Goldreich ( 1997 ) and is given by H ( r ) = r H 0 / R 0 ( r / R 0 ) 2/7 . The ratio H 0 / R 0 0.1 defines cold discs whereas H 0 / R 0 > 0.1 defines hot discs according to Faure, Fromang Latter ( 2014 ). Additionally, typical values for protoplanetary discs range from 0.1 to 0.3 (Ono, Nomura Takeuchi 2014 ). Hence, for a generic case, we adopted the value of 0.17. 4.2 Dust and ice model Because the interaction between light and matter in astrophysical environments is regulated by absorption and scattering processes, we calculated the opacity for a core of silicate 1 (Weingartner Draine 2001 ) with the inclusion of amorphous carbon and ice (H 2 O:NH 3 :CO 2 :CH 4 ) to simulate the presence of a mantle. The carbon inclusion was assumed to be 0.15 (Pontoppidan et al. 2005 ), and the abundances of ice relative to H 2 were 10 −4 for water and 10 −5 for CO 2 , CH 4 and NH 3 . To perform the mixing rule, we adopted the Maxwell–Garnett effective medium theory (Bohren Huffman 1983 ) to calculate the effective CRI for the grains. Considering that the relation between the complex dielectric function () and CRI () for non-magnetic materials is given by , the equation for the effective CRI () is given by where and are the CRI for the silicates and for inclusions, which can be carbonaceous material or ices, respectively. The opacity for the grains was calculated employing the Mie theory (Mie 1908 ), assuming spherical grains with a single grain size of 0.3 μm. Figs 6(a) –(c) show the opacities for the grains considering the Fluence 0, Fluence I (10 11 ions cm −2 ) and Fluence II (10 12 ions cm −2 ). As can be seen in Fig. 6 , the CRI presented in this paper allows us to calculate an opacity data base to be used in astrophysical models. This type of data base has been created by Ossenkopf Henning ( 1994 ), although such data are consistent only for non-processed regions in the ISM. However, the processing of the ice is a common scenario and the opacities from Ossenkopf Henning ( 1994 ) lead to wrong conclusions about the chemical evolution of the ice. In this way, the data base presented in this paper can be used to calculate new opacity tables, by using realistic data of processed ices, as well as realistic grain geometry. Figure 6. Absorption and scattering opacities of astrophysical grains employed in this paper. Panel (a) presents the opacities of bare silicate and panels (b) and (c) present the opacities of silicate with ice at Fluence 0, I and II. The lines were moved arbitrarily to highlight differences due to energetic
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