engleski

Do cement nanoparticles exist in space?

Calcium silicate hydrate is used to model the properties of cement on Earth. We study cementitious nanoparticles and propose these structures as components of cosmic dust grains. Quantum density functional theory methods are applied for the calculation of infrared spectra of Ca4Si4O14H4, Ca6Si3O13H2 and Ca12Si6O26H4 clusters. We find bands distributed over the near-, mid- and far-infrared regions. A specific calcium silicate hydrate spectral feature at 14 μm, together with bands at 10 and 18 μm, which exist for other silicates as well, could be used for the detection of cosmic cement. We compare the calculated bands with the 14-μm features in the spectra of HD 45677, HD 44179 and IRC+10420, which were observed by the Infrared Space Observatory and classified as remaining. A high abundance of oxygen atoms in cementitious nanoparticles could partially explain the observed depletion of this element from the interstellar medium on to dust grains.

astrochemistry ; numerical methods ; infrared spectroscopy ; cement nanoparticles ; cosmic dust

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