摘要：Observationally, both the 3.4μm aliphatic hydrocarbon C-H stretching absorption feature and the 9.7μm amorphous silicate Si-O stretching absorption feature show considerable variations from the local diffuse interstellar medium (ISM) to Galactic center (GC): both the ratio of the visual extinction (AV) to the 9.7μm Si-O optical depth (Δτ9.7 μm) and the ratio of A V to the 3.4 μm C-H optical depth (Δτ3.4 μm) of the solar neighborhood local diffuse ISM are about twice as much as that of the GC.In this work, we try to explain these variations in terms of a porous dust model consisting of a mixture of amorphous silicate, carbonaceous organic refractory dust (as well as water ice for the GC dust).
