Modelling absorption of electromagnetic radiation by carbon-based constituents of the interstellar medium

This proposal will investigate the hypothesis that carbon in an amorphous aggregate state forms particles of interstellar matter. This will be achieved by using the well-known property that amorphous carbon lacks long range order. As a result of this property, the process of absorption of electromagnetic radiation by amorphous structures appears locally and similar to that for molecules. As a result the electronic energy spectra of small molecular clusters of carbon in different forms will be investigated by performing ab initio calculations. A primary purpose of these calculations will be to understand the propensity of these small clusters for absorption of electromagnetic radiation.The results from the small carbon clusters will be used to parameterise an empirical many body potential function which will be used to examine the structure of amorphous carbon of different densities on a much larger scale than can be achieved using ab initio calculations alone.