A CRYSTAL-based parameterization of carbon atom dynamic polarizabilities to compute optical properties of curved carbonaceous nanostructures.

The radiative forcing of dust particles in Earth atmosphere is still poorly characterized. A better estimation of the absorption cross section of dust particles in the UV-visible part of the spectrum is thus needed. Among the methods used for this purpose, the Atomic Point Dipole Interaction model has the distinctive advantage of being sensitive to the atomistic geometry of the particle and to the chemical functions it contains. However, this requires an adequate parameterization of the atomic polarizabilities for all the atomic species forming the particle, over the UV-visible spectrum. In this paper, we illustrate how new methodological improvements based on quantum chemistry, allow taking into account the curvature of the carbon network in the parametrization of the carbon atomic polarizabilities, using the C 60 molecule to fit the adequate set of parameters. We thus show how this leads to significant differences in the computed curves of the absorption cross section of pure carbonaceous nanoparticles as a function of the frequency, with respect to calculations performed using parameters issued from graphite. [ABSTRACT FROM AUTHOR]