Link to have access to the "qabs" open access code and its source to calculate the opacity of icy interstellar ices from IR and THz measurements. The code computes Qabs, Qsca, and Qext from the refractive index or the dialectric constant using Mie's theory. It also compute opacity for coated materials. https://bitbucket.org/tgrassi/compute_qabs/src/master/ The link redirects you to an open access environment where to execute the code properly.